Startup Idea: Automated eBay Fee Tracker and Calculator

Startup idea to develop a software that can automatically track and calculate eBay and PayPal fees for small business owners. The software should be capable of updating in real-time when eBay alters its rates, processing returns, and handling files from eBay in database format.

I run a small business on the side, although I used to run it full time. It's an ebay business. Ebay does very little to help us understand the fee breakdowns. Software that automatically updates when ebay changes their rates would be helpful. In the past, I used an online website to calculate fees. However when ebay would tweak the fees, the calculator would not update and would become totally useless. I need software that helps me track all my costs, but specifically ebay fees: listing fees, final value fee, and PayPal fees as well. Software should be able to download files from ebay in database format and software should help me process returns - ebay does not always automatically reverse final value fees when an item is returned. I have to call them. I charge 20% restocking fee. Every time I need to figure out how much of a final value fee credit I am due and I have to call them up (they are cheating us, I cannot wait until they are sued). Anyway! I would love to have a tool to do this instead of figuring it all out by hand! This is NOT price tracking...this is just a tool to help navigate their deliberately confusing fee structure. (And the sometimes-you-have-them-sometimes-not discounts as well. Some months I get 20% off, some not, so...yeah, it's a pain.).