[SOLVED] How to calculate accumulate amortization, Residual value, and VLook up

Hello,

I have a royalty calculation spreadsheet. I would like to ask for help with the following formula.

1) I need to calculate the accumulate amortization as of B10.
2) I need to find the Residual value
3) The formula on O3 need to be able to auto lookup the corresponding product with the royalty period and calculate the monthly cost. Now the formula is a fixed formula, the end result is correct but I can not add row and fill it cross.

Attached is the sample.

Greatly appreciate your help.

Jackson