If you have this months meter reading in D2 and last months in C2 then
this formula will give the units used

=MOD(D2-C2,100000)

If you set up your spreadsheet with each meter on a separate row,then
you can have a meter identifier in column A and first date's readings
in column C, second date in D etc. (row 1 contains meter reading date).
In B2 copied down you could use this formula

=MOD(LOOKUP(100000,C2:IV2)-LOOKUP(100000,C2:IV2,B2:IU2),100000)

which will automatically give you the units used for the last month


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daddylonglegs
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