Maximum Interest Rate/ Effective Interest Rate

Hi John For a borrower - He limits his maximum interest rate payable by exercising his put option right? As per your lecture the max interest rate/effective interest rate =strike price + spread + premium However I have tried various questions and checked the effective interest rate the above way- it doesn't match with the actual effective interest rate paid. I will write down the rates I got from all the interest rate option questions in this order ( rate using the lecture method/actual effective interest rate paid) 1) Alecto (Pilot Paper) - We exercise the option when interest rate moves to 3.8% and strike rate is 3.5%-Contracts rounded off to 37 from 36.67 (4.88%/4.70%) 2) Phobos (Dec 2008) - if we select strike rate as 6% we will exercise it when interest rate moves to 7%-Contracts are exact 80. (6.668%/6.628%) - I thought the difference was due to rounding of contracts until I did this question. 3)Keshi (Dec 2014) - If we select 4.5% as strike rate , we will exercise when interest rate moves to 4.3%-Contracts are exact 42 (5.562%/5.342%) 4)Daikon (June 2015) - 62 contracts exact Interest rate moves to 4.4% Exercise price 4.5% - (5.504%/5.344%) Exercise price 4.0% - (5.208%/5.048%) 5)There is a slight difference between the rates in your lecture as well. What is the reason for this ? There is a difference between the rates even when we are a lender.