I know what you mean. Figuring out the the bandwidth points for all of the adapters is a bit confusing... Here is a secret: It doesn't matter!
Even though each PA is assigned a certain number of bandwidth points and the router has a maximum number of points, exceeding that number if often fine, especially if you know that the circuits will not be operating near capacity. For example, I had a 7206VXR/NSE-1 which is listed as (I believe) 600 bandwidth points. In it I had 2 PA-GE's (400 points each), a few FE's and some DS-3 PA's. The total bandwidth points were something like 1100, and the router would complain that we had "Exceeded Bandwidth Points", but we never saw any problems (like queue drops or similar things...). So, yes, assuming your FE's are not horribly busy, slap another PA in your box!