Please find the attached.
You could easily see a flaw (on the Sheet 7a), namely,
there are Account IDs which have not full (three) Periods
to calculate a Baseline, so there could be different Baselines
for the same Owner at different Periods.
To cope with that fact, one should decide upon a logic to apply
to missing Periods for those Account IDs -- should one add empty rows
(mean there are zero sales for a particular Period), or calculate a Baseline
from existing Periods only, or keep everything as is.
Growth Example_YF.twbx 100.1 KB