I got the Fundraising plugin, but we need it to reflect taxes applied to the donations we receive.

We love how this plugin works, but we are struggling with getting the actual donations to display correctly. It works well in reflecting the whole amount of a donation received, but PayPal applies a tax that does not get reflected. This makes the amount raised inaccurate. I thought setting up the IPN would resolve the problem, but after making a test donation we are still seeing it occur. Any ideas? Thanks!