Compare Excel Data in two columns formula

I have data I need to compare in two columns. Column A & B are the serial numbers and amounts that we gave discount for. Column E & F are the serial numbers and amounts corporate reimbursed us for. We need to to compare the data, and highlight column A&B where the amount reimbursed has a variance for greater than $20 or nothing was paid at all. Red would be prefered color. You need to make a Vlookup for match formula. All Data is in "Compare Data Sheet".