OK if your manager has you on the right duty pattern then it may be simpler than you think
If and I stress IF your duty pattern on PSP is correct then unlike the old leave system it will not take 5 days off you and credit one back, it will only take 4 days off you in the first place
Meaning you are not owed days back as PSP knew it was your day off and only used 4 days a/l instead of 5
What you need to do is ask to see your last years leave on PSP and check if on those weeks it took 4 or 5 days off you. If it took 4 then all well and good and no days are owed, if it took 5 then your duty pattern is not correct and you will be owed days back
It is a major difference between the old way of doing leave ( where your leave card is still printed from) and the new way (PSP) and causes untold confusion
So my advice is check first what was taken from your leave on these weeks and go from there