Geez, it took me 5x to re-read in order to comprehend with your concern
This took my attention
in this moment buy price limit 0.0009 btc , sell price limit 0.0007 btc
the website calculate the price of eos/btc for market price is 0.0008 btc
The heck why are you buying at the high price and sell at the low price??
Of course, the system will not allow you to buy at the price higher than the actual market price
If you do this, it will give you the market price instead, and this is same with the limit sell