I am having the same problem, but mine is for regular 7 day listings, NOT a 30 day listing.
I listed something Auction Style for $25.99 with a BIN of $29.99 and when I hit the estimated Ebay costs I get $1 for insertion fee and $1 (for a total of $2 bucks). I just confirmed with Ebay support that BIN should be 20 cents, so my total should be $1.20.
I filed a support ticket, just to be sure they are aware that its not only 30 day listings that are messed up.