I have a spreadsheet that calculates utility usage for commercial tenants in
a building. The top worksheet tab contains a table of utility readings by
tenant and below is a table that calculates usage (Current minus Prior
reading * meter multiplier). Below that I enter the utility periods, costs
and utility units to determine $/KWH, $/Therm or $/gallon of water. Below
that I have a table that multiples usage by cost per unit to get billing
amount for each tenant during that period. So my top worksheet tab is a
summary of billing for the whole year.

Each worksheet tab below contains one invoice I create for every tenant.
Each invoice is linked to the top tab to get Current and Prior meter readings
along with cost per unit. My question is how can I simplify updating the
Current and Prior meter reading data on each of the 25+ invoice tabs?

Thanks,
Ken