Ryzom API

Character: Misugi
Server: Aniro
Request: http://atys.ryzom.com/api/character.php?part=items&key=xxxxxxxxxx

XML returned:
<item s="10" q="34" price="428" quantity="10" in_sell_since="1274003213" continent="fyros">m0016dxafd01.sitem</item>
If I calculate the time left I find: 6 days, 22 hours and 38 minutes

But in-game, I have another time !? (5 days, 6 hours)