lulupon, could you set changing pool diff only when new block was found? because i have a lot of (10%) rejected shares.
If you have high rejected shared, please add "+0.001" after wallet address. It provides fixed difficulty to your miner. (You can put other values also.)
Example : minerd -o stratum+tcp://pool.lulupon.net:54093 -u 7NSHRu6sEAekCxZofeifL3KTuNkk1Fo15C+0.001 -p x