First may I start by saying that all 3 of your questions can be answered by watching our free lectures. They cover everything needed to pass the paper well. In calculating the simple payback period, finance costs are not typically included. The simple payback period focuses on the time it takes to recover the initial investment in cash terms, without considering the time value of money or financing costs. The payback period is based on the cash flows of the project and does not involve the inclusion of finance cost. Equally in discounted payback all financing costs should be ignored as the cost of financing is accounted for in the discount rate used.