From what you've described, I believe you can use:
=TEXT(DATE(YEAR(TODAY()),MONTH(TODAY())+MOD(DATEDI F(TODAY(),DATE(YEAR(TODAY())+1,MONTH(DATEVALUE("1-"&$G23&"-"&YEAR(TODAY())))+1,0),"ym"),(12/2^($D23-1))),1),"MMM")


in I23 (assuming that's where the expected results are to go), then copied down as far as needed.

FWIW, with the above formula, you don't really need the group tables (they aren't referenced). I'll leave it to you to figure out how the formula calculates the review intervals for each group. However, if you want to output the review schedule for each student, you would need to keep the group tables and use:
=OFFSET($A$1,MATCH($G23,$B$5:$B$16,0)+3,MATCH("Gro up " &$D23,$B$2:$O$2,0)+2)
in, say, J23, then copied down as far as needed.

PS: The board software puts spaces in the first formula where there shouldn't be any. In this case, 'DATEFI F' is 'DATEDIF'.

__________________
Cheers,
Paul Edstein
[Fmr MS MVP - Word]

Thanks. This may solve many a problem (for me anyway). I'll start playing with it this morning and feed back once I'm sure I haven't screwed something up.

We have a winner!

It works like a champ. I'm poking at it a bit to understand what you did, but thanks a bunch. It will save me lots of time and very elegantly I must say.

Well I thought we had it solved, but I guess I was too eager. Someone found a flaw and I rechecked the original. For some reason it’s not working properly. The expected result for line 21 (Student 19) should be May, but it shows up as Apr. I went back and checked the original sample and the formula

=TEXT(DATE(YEAR(TODAY()),MONTH(TODAY())+MOD(DATEDI F(TODAY(),DATE(YEAR(TODAY())+1,MONTH(DATEVALUE("1-"&$G23&"-"&YEAR(TODAY())))+1,0),"ym"),(12/2^($D23-1))),1),"MMM")

gave the same results. Everything was fine until the date changed to 04/29/14 then the result changed from May (which was correct) to April which is wrong. It should have been May until 06/01/14 then it would change to Aug. Thanks for looking at it again and I do appreciate your time.

Attached Files

Revised Sample Problem.xlsx (14.9 KB, 22 views)