Premium charge question

I would like to clarify I have never paid premium charge due to my overall charges being 39% approx of my gross profit. My query is in relation to a link I use that shows how much I won /lost the previous week and how much commission I paid. I have been monitoring this for about 6 weeks now and it doesn't seem to quite tally up, each week my gross profit is roughly £100 down on what the link says and my commission paid is about 3% more than what it states. Is this something I should be concerned with or am I so far away from paying this that I should let it rest? any opinion would be appreciated.David.