Buy It Now isn't the same as Fixed Price.
However, eBay uses the same BIN button for both formats.
Buy It Now is used as an extra within an 'auction' style listing.
A fixed priced listing is just that, fixed. A buyer cannot and does not bid on the item.
So today, eBay is offering a set fee of .10 for all Fixed Priced listings. You need to switch your 'format' from 'auction' style to 'fixed price' style to receive the .10 sale price.
I hope this helps. Now get listing!