I think if you post (for example) 2 stacks of 25mil a few hrs apart and someone buys 50mil from the AH, with your stock next in 'line' - I THINK your oldest 25 mil sells and the other 25mil of the order goes to the next auction time wise (someone else's - whoever posted just after your first batch - leaving your next batch a few sales behind, if ever)
I'm no expert just what I've read places, so if you post 500, and your stock is in line, that full sale of 50 mil (as well as any orders after that of any size) goes to you... as opposed to only 25
I'm either wildly off base or this is actually true - I'd be interested if someone can confirm this.
Up to you, personally I post everything on the account, but have 5 setup, auctions range from 15-100 mil per