Is there any positive or negative impact on mining if I manually set the "suggest-diff" value higher than what the pool is currently feeding my miners?   

I have some old dusty S7's that are running around 4.4k diff and the utility is 17.  Was wondering if it hurts or helps anything setting diff to 10k or even higher. Last time I tried it the utility dropped to 5 but was getting much higher bestshare. Just wondering if tweaking that setting has any benefit.