i can't speak for Optionsexpress as i have never used it
but i just started paper trading last month with my Optionshouse account and i feel like chasing all trades, i only get fills at ask or bid price and not anywhere near to mid, not sure if its same with real account too
but at opening bell i get weird fills way below market or way over market if i have GTC orders
i think we have to take a step ahead and open a TOS or IB account and fund it
then only we can actually trade ad get a feel for the strategies used here