Control Charts Warning Test

[#1]

How does JMP decide which point to mark as OOC? For example, in below image why is it that only the two points towards the right marked as red? It fails for Test 7 (15 points in a row in Zone C or beyond). 

a

[#2 · Accepted solution]

If you count the points that start appearing in zone C or above, the 15th data point is marked in red, as is the 16th data point.  However, after that point, the next point is in zone B, thus resetting the counter for rule 7.