I'm not at all familiar w/ S3 programming, but if it's like most...
What happens at line 50 if INP1 is NOT on? Most languages I know will ignore the line and skip to the next - which is line 50. So whether or not INP 1 = 1, Line 50 executes the call to PROG1.
Remembering what I said about being unfamiliar w/ S3, it looks like you need something like:
Code
40 JUMP TO 60(line) IF INP 1 = 0
50 CALL PROG1
60 JUMP TO 80 IF INP 2 = 0
70 CALL PROG 2
80 ...
It might be worth mentioning that if the pushbutton is not held (or latched on), the programs don't get called. If both buttons are held, both programs execute.