I think it's worth updating you, progress is slow, but I'm doing my best to be consistent, hopefully after the x-mas chaos, and with my health improving things will pick up again.
I've had a few issues with fee calculations, take a look at this:
Closing Fee over �600: (From: eBay.co.uk Fees)
5.25% of the initial �29.99 (�1.57), plus 3.25% of the initial �30.00 - �599.99 (�18.53), plus 1.75% of the remaining closing value balance
Have you ever looked at how complicated ebay fees can get ? I've had a bug reported that closing fee's weren't being calculated correctly, basically I typo'd a > rather than >= and this was causing the function to fail under certain circumstances, the up-shot, closing fee's not being added to some transactions.
99p listing fees were also effected by a similar bug - DOH !
Anyway onto some good news, I shall be focusing on two new features (todo page updated), 1 improving the work flow so things feel quicker, the server and page response is excellent, but users just feel they are spending too much time typing stuff in; so I'm going to add a Sell Similar function - like what ebay do. The second will be fee variations, so shops & non-UK users can get involved !
The help section has also been updated with an link to us page so you can now share your favorite calculator with the world !
These are the graphics I've done so far, if you're a paint wizard, please let me know.