How do you calculate a student's Pell Enrollment Intensity based on prior course enrollment?

Summary:

Hello folks, we are having an issue properly calculating Pell enrollment intensity for a subset of students beyond the census date. For most students if the census date has already passed our script is returning the enrollment intensity from their previous financial plan, but some students won't have a previous Pell enrollment intensity for a certain semester when being packaged after the census date. This will include students who for one reason or another do not receive their first ISIR for the year until after census date, and students who did have an ISIR before the census date but did