We could set difficulty to even lower but you will not get paid for that. Because network reject all shares with diff less that 1. What is more important to you got paid or submit usless shares? Next block you could submit more at the same time and the other miner will have no shares, so you will have highe percentage and higher reward as well. So it's only matters
if you switch from pool to pool at short period of time. Stay with one pool for 24h and then compare to other!