Heli, I am not sure how to get your doctor to change the hydro/apap ratio. Around here, I don't think doctors even know about the 10/325's.
I'd think mentioning it to your doctor would be predicated on how much you have been prescribed and for how long.
If you are to take 1 or 2 tablets 4 times a day, and are taking 5-8 tabs daily, then I think you could validly bring up the APAP issue. Just say you read about a drug that had the same amount of hydrocodone and a lower amount of APAP in each pill and could you try it?
You might also consider SAM-E or milk thistle or some of the other thinks available to help your liver detox from the APAP.

I do not believe hydrocodone itself has a limit... it is the APAP that it is combined with that would determine a safe limit.