diff --git a/lib/sensiplan.js b/lib/sensiplan.js
index a9ad09d..1364665 100644
--- a/lib/sensiplan.js
+++ b/lib/sensiplan.js
@@ -3,15 +3,22 @@ function getTemperatureStatus(targetDateString, previousDaysInCycle) {
     .filter(day => day.temperature)
     .map(day => !day.temperature.exclude && rounded(day.temperature.value, 0.05))
 
+  let detectingPotentialHighLevel = false
+
   return tempValues.reduce((acc, curr) => {
     // if we don't yet have 6 lower temps, we just collect
     // if no shift has been detected, we collect low temps
     // after the shift has been detected, we count them as part
     // of the higher temperature phase
-    if (acc.low.length < 6 || (!acc.shiftDetected && curr <= acc.ltl)) {
+    if (acc.low.length < 7) {
+      acc.low.push(curr)
+      acc.ltl = Math.max(...acc.low.slice(-6))
+      // TODO these are the same
+    } else if (curr <= acc.ltl && !detectingPotentialHighLevel && !acc.shiftDetected) {
       acc.low.push(curr)
       acc.ltl = Math.max(...acc.low.slice(-6))
     } else {
+      detectingPotentialHighLevel = true
       acc.high.push(curr)
     }
 
@@ -19,10 +26,12 @@ function getTemperatureStatus(targetDateString, previousDaysInCycle) {
     // we round the difference because of JS decimal weirdness
     if (acc.high.length === 3 && rounded(curr - acc.ltl, 0.01) >= 0.2) {
       acc.shiftDetected = true
+      detectingPotentialHighLevel = false
     }
     // 1st exception rule
     if (acc.high.length === 4 && curr > acc.ltl) {
       acc.shiftDetected = true
+      detectingPotentialHighLevel = false
     }
 
     return acc
diff --git a/test/fixtures/first-exception-rule-no-shift.json b/test/fixtures/first-exception-rule-no-shift.json
new file mode 100644
index 0000000..559aefb
--- /dev/null
+++ b/test/fixtures/first-exception-rule-no-shift.json
@@ -0,0 +1,67 @@
+[{
+  "date": "2018-06-04",
+  "temperature": {
+    "value": 36.7,
+    "exclude": null
+  }
+}, {
+  "date": "2018-06-05",
+  "temperature": {
+    "value": 36.57,
+    "exclude": null
+  }
+}, {
+  "date": "2018-06-06",
+  "temperature": {
+    "value": 36.47,
+    "exclude": null
+  }
+}, {
+  "date": "2018-06-07",
+  "temperature": {
+    "value": 36.49,
+    "exclude": null
+  }
+}, {
+  "date": "2018-06-09",
+  "temperature": {
+    "value": 36.57,
+    "exclude": null
+  }
+}, {
+  "date": "2018-06-10",
+  "temperature": {
+    "value": 36.62,
+    "exclude": null
+  }
+}, {
+  "date": "2018-06-11",
+  "temperature": {
+    "value": 36.55,
+    "exclude": null
+  }
+}, {
+  "date": "2018-06-12",
+  "temperature": {
+    "value": 36.8,
+    "exclude": null
+  }
+}, {
+  "date": "2018-06-13",
+  "temperature": {
+    "value": 36.86,
+    "exclude": null
+  }
+}, {
+  "date": "2018-06-14",
+  "temperature": {
+    "value": 36.77,
+    "exclude": null
+  }
+}, {
+  "date": "2018-06-15",
+  "temperature": {
+    "value": 36.57,
+    "exclude": null
+  }
+}]
\ No newline at end of file
diff --git a/test/fixtures/regular-rule-no-shift.json b/test/fixtures/regular-rule-no-shift.json
new file mode 100644
index 0000000..ca99c5a
--- /dev/null
+++ b/test/fixtures/regular-rule-no-shift.json
@@ -0,0 +1,61 @@
+[{
+  "date": "2018-06-04",
+  "temperature": {
+    "value": 36.7,
+    "exclude": null
+  }
+}, {
+  "date": "2018-06-05",
+  "temperature": {
+    "value": 36.57,
+    "exclude": null
+  }
+}, {
+  "date": "2018-06-06",
+  "temperature": {
+    "value": 36.47,
+    "exclude": null
+  }
+}, {
+  "date": "2018-06-07",
+  "temperature": {
+    "value": 36.49,
+    "exclude": null
+  }
+}, {
+  "date": "2018-06-09",
+  "temperature": {
+    "value": 36.57,
+    "exclude": null
+  }
+}, {
+  "date": "2018-06-10",
+  "temperature": {
+    "value": 36.62,
+    "exclude": null
+  }
+}, {
+  "date": "2018-06-11",
+  "temperature": {
+    "value": 36.55,
+    "exclude": null
+  }
+}, {
+  "date": "2018-06-12",
+  "temperature": {
+    "value": 36.8,
+    "exclude": null
+  }
+}, {
+  "date": "2018-06-13",
+  "temperature": {
+    "value": 36.86,
+    "exclude": null
+  }
+}, {
+  "date": "2018-06-14",
+  "temperature": {
+    "value": 36.77,
+    "exclude": null
+  }
+}]
\ No newline at end of file
diff --git a/test/fixtures/regular-rule.json b/test/fixtures/regular-rule-shift.json
similarity index 100%
rename from test/fixtures/regular-rule.json
rename to test/fixtures/regular-rule-shift.json
diff --git a/test/sensiplan.spec.js b/test/sensiplan.spec.js
index 25ab34e..055f6db 100644
--- a/test/sensiplan.spec.js
+++ b/test/sensiplan.spec.js
@@ -1,40 +1,66 @@
 import chai from 'chai'
 import { getTemperatureStatus } from '../lib/sensiplan'
-import tempShift from './fixtures/regular-rule.json'
+import tempShift from './fixtures/regular-rule-shift.json'
+import noTempShift from './fixtures/regular-rule-no-shift.json'
 import lowerTempDays from './fixtures/lower-temps.json'
 import firstException from './fixtures/first-exception-rule.json'
+import firstExceptionNoShift from './fixtures/first-exception-rule-no-shift.json'
 
 const expect = chai.expect
 
 describe.only('sensiplan', () => {
   describe('getTemperatureStatus', () => {
-    it('reports lower temperature status before shift', function () {
-      const status = getTemperatureStatus('2018-06-09', lowerTempDays)
-      expect(status).to.eql({
-        low: [36.7, 36.55, 36.45, 36.5, 36.55],
-        ltl: 36.7,
-        high: [],
-        shiftDetected: false
+    describe('regular rule', () => {
+      it('reports lower temperature status before shift', function () {
+        const status = getTemperatureStatus('2018-06-09', lowerTempDays)
+        expect(status).to.eql({
+          low: [36.7, 36.55, 36.45, 36.5, 36.55],
+          ltl: 36.7,
+          high: [],
+          shiftDetected: false
+        })
+      })
+
+      it('detects temperature shift correctly', function () {
+        const status = getTemperatureStatus('2018-06-14', tempShift)
+        expect(status).to.eql({
+          low: [36.7, 36.55, 36.45, 36.5, 36.55, 36.6, 36.55],
+          ltl: 36.6,
+          high: [36.8, 36.85, 36.8],
+          shiftDetected: true
+        })
+      })
+
+      it('detects missing temperature shift correctly', function () {
+        const status = getTemperatureStatus('2018-06-14', noTempShift)
+        expect(status).to.eql({
+          low: [36.7, 36.55, 36.45, 36.5, 36.55, 36.6, 36.55],
+          ltl: 36.6,
+          high: [36.8, 36.85, 36.75],
+          shiftDetected: false
+        })
       })
     })
 
-    it('detects temperature shift according to regular rule', function () {
-      const status = getTemperatureStatus('2018-06-14', tempShift)
-      expect(status).to.eql({
-        low: [36.7, 36.55, 36.45, 36.5, 36.55, 36.6, 36.55],
-        ltl: 36.6,
-        high: [36.8, 36.85, 36.8],
-        shiftDetected: true
+    describe('1st exception rule', () => {
+      it('detects temperature shift', function () {
+        const status = getTemperatureStatus('2018-06-14', firstException)
+        expect(status).to.eql({
+          low: [36.7, 36.55, 36.45, 36.5, 36.55, 36.6, 36.55],
+          ltl: 36.6,
+          high: [36.8, 36.85, 36.75, 36.65],
+          shiftDetected: true
+        })
       })
-    })
 
-    it('detects temperature shift according to 1st exception rule', function () {
-      const status = getTemperatureStatus('2018-06-14', firstException)
-      expect(status).to.eql({
-        low: [36.7, 36.55, 36.45, 36.5, 36.55, 36.6, 36.55],
-        ltl: 36.6,
-        high: [36.8, 36.85, 36.75, 36.65],
-        shiftDetected: true
+      it('detects missing temperature shift correctly', function () {
+        const status = getTemperatureStatus('2018-06-14', firstExceptionNoShift)
+        expect(status).to.eql({
+          low: [36.7, 36.55, 36.45, 36.5, 36.55, 36.6, 36.55],
+          ltl: 36.6,
+          high: [36.8, 36.85, 36.75, 36.55],
+          shiftDetected: false
+        })
       })
     })
   })