Specifically, look at Call Meter 3G. THAT app is flexible enough to accomodate almost ANY calling plan, voice AND text. 

You need to also put in a warning: that the app cannot detect the network so anything about "free in-network" minutes or text cannot be separated. You also can't do anything about "family plan" where more than one line share minutes as you can't see what the other phone used. 

CRAZY IDEA: For calling, you may even want to let users upload / download defined profiles for certain carriers. For example, download Verizon plan / T Mobile Plan, and so on.