Comment by maxander

This sort of story probably fully explains origins of the OP's lament (that AWS billing is so opaque that even internal Amazon teams can't figure it out.) Some AWS middle manager knows that if he orders better billing tools to be implemented, AWS income will drop; not significantly, but ~$700 multiplied by the number of AWS users might make enough of a dent to be noted in his performance report. In order to make this omission more plausible, even internal investigation tools (which would encourage infrastructural improvements that make user-facing tools easier to build) are neglected.