Guild Wars 2

So i know that to sell an item, the TP will take away 10% as tax and another 5% for listing fee that make it 15%. Let say you sell one item for 1 000 000c which is 100g (1g = 10 000c), subtract 15% you get 850 000c which is 85g. Correct?

Today i tried to sell 250 pumpkin for 37c each. if we do the math, without calculating the tax i should get 37 *250 =9 250c which is 92s50c, if i subtract 15% tax from it, i should get 78s62c. But base on the number the TP gives me, i will only get 77s87c. see the picture.
http://i1227.photobucket.com/albums/ee440/dg2903/tp_zps3ccfaf72.png

What’s going on here? did i make a mistake while calculating?

Bumb. still looking

I have one lvl 80 Guardian and I’m working on an Archer. I enjoy WvW alot and also like doing dungeons. I’ve been joining while a lot of different guilds since i started playing but non of the guild i joined fit me. I need a guild that is heavy on WvW (it would be great if we have WvW daily) and also on dungeons, i am not looking for a mindless zerg fest wvw guild, i want a guild that is organize and friendly. I prefer a guild on Tarnish Coast, if you from a different server, go ahead hit me up, i will give it a thought.