Getting incorrect results from Prog-Plan-Subplan query

CS 9.2 PUM 29, PT 8.60.06

I am writing a query (app engine) that returns program, plan, and subplan. It works correctly except for when a student added a subplan and then dropped it.

There are three attachments:

#1: Prog-Plan-Subplan query data.xslx is all the original data for student xxx

#2: Prog_Plan_Subplan query.txt the the SQL I am using

#3: Prog-Plan-Subplan query result.xlsx is the result of the query

In #1, you can see that the student added a subplan and then dropped it, but when I execute the query, I still get a subplan in the result. How do I structure the query so that I no longer get the subplan?