Week over week Match-Index Help

I need to have the Totals column in the % change for week over week automatically take the last two weeks when I insert a new week. I'm using the Index-Match w/ Max function. For ex, Row 5, I have the correct answers. Row 6 uses the index formula, which is computing incorrectly. I cannot find where it is wrong. Please help.

The spreadsheet is attached. Thank you in advanced!