I am working out a way to make sure they tally up, i.e. that i am not
paying the same consumption twice.

i have went over my last few bills and found various complications. i
have received bill s for estimated consumption, & acutal consumption,
for periods of variying numbers of days with dates which overlap.

does anyone here bother to check their bills? do you use some kind of
software or excel sheet to do it?

thx