Interesting... You are saying this is front end and you use POCLBM miner... Not familiar with that one... I notice that hashrate gui vs cgminer is +10% if you use cgminer... What is POCLBM like?
My program is similar in concept to GUIMiner, and both programs use POCLBM as a backend (at least, POCLBM is the default backend for GUIMiner). POCLBM is a command-line miner written in Python, it doesn't take input like cgminer (you have to specify options when you first run it), but the corporate anti-virus at my office blocks cgminer as a virus so I can't use it there
To fix the 10% rate problem, run SlushMiner as an administrator. I've had another user complain about that problem, but it went away when he ran it as admin. I need to look into that problem...