I am due for my ILR appointment in 2 weeks time and have a sticky situation.

I have been on Tier 2 general visa for past five years. However, I have been undergoing a part time MBA due to which I have overshot my leave allowances by ~ 21 days. the latest month salary slip mentions UNPAID LEAVE in deductions section.
In total I have not exceeded 180 days of stay outside UK. Including the unpaid leaves its 96 days in 5 years.
Question:
1. What does the guidance notes [Set (o)] advise in such circumstances? Is unpaid leave allowed?
2. should I get the Payslip description of 'Unpaid Leave' changed to 'other deduction's if that's an option?
3. What supporting documents would I need?
Thanks in Advance.