I noticed the pool starts off with difficulty of 1024 and then after a while mine drops down to one and then climbs up before stopping at 4.
The reason for the 1024 diff at start is so that a really high rate ASIC doesn't overload the pool before the auto-diff adjusts. And the reason for having the lower diff at all is so that you can verify with the pool stats what your approximate hash rate is to see if it match's, roughly, what your mining software is reporting. It has no effect on the chances of your finding a block.