I don't know why anyone has an issue ABing in stamp without advanced. I have just normal settings, and AB in stamp often. I miss a lot, but usually in every stock I'm getting something. I only have it set to buy UB stamps too. I let it run overnight last night and had 8 UB stamps from it.
You must be pretty lucky then. I left it from 3AM-6AM and got 1 stamp lol.
There's a lot of AB'ers in there but sometimes you get a good night.