Several Checkbox's in Numbers, Use Last Checkbox Data ONLY

Question

Hello,
I Need some help.
Here is what I want to achieve:
I need Data in 1 cell on WHEN a Job was last done. I curently have checkboxs which are ticked each month when the Job is completed, I need a cell to look at all checkboxes for the year and use the LAST checkbox that is ticked to tell me when Job was last done.
What I have done so far:
Date is above checkboxes for date Job done
so formula in cell is: =SUMIF(G2,"=true",G1) G2 = Tickbox & G1 = Date Job Done
BUT I need it to do same thing for every tickbox for the year and cell uses data from last tickbox in that year.
Hope that make sense but i NEED help

Answer 1

MJ,
This solution uses an auxiliary table to facilitate the last date determination.
It also employs some hidden columns in the main table. If a Done box is checked, the date for that done box is repeated in the done box row. That content is picked up in the auxiliary (Dates) table, which collects all the done dates in the Main table. Back in the Main table, the next service date picks the max date from the Dates table for each row and adds the appropriate number of days.
Here are the formulas...
Next serv due:
=MAX(Dates :: 2:2)+E*7
Paste formula into first data row and Fill Down.
Column J serevice date:
=IF(G, H$1, "")
Fill Down and copy to other service date columns
Dates Table, cell B2
=IFERROR(INDEX(Main, ROW()+1, COLUMN()*4+2), "...")
Fill Across, then Fill Down
Let me know if you have any questions or if I have left anything out.
Jerry