How to make a selection of the desired value from the table according to the nearest suitable one?

Question

Microsoft Access

Good afternoon dear!
I ask for hints in a simple question for you:
I have two tables.
By the value of tabl2.Count, we find the appropriate value of tabl1.0.85 through the condition tabl2.COUNT = tabl1.Number and group by tabl2.IGE.
How to fulfill the condition: find subtotals (if COUNT=43, then accept as for the number 40, for example; if COUNT=104, then accept as for the number 60)

As a result, I get a table in Fig. 4 and cannot "pull" the missing data . I tried switch and IIf, but I didn’t know where and how to apply it correctly (don’t scold me too much).





Thanks in advance!