You're making things much more difficult for yourself than need be.  You
still need to validate that they've entered the columns before you can
validate the totals.  Whether you realize it or not, you are trying to
validate a SET or subset of data...which would be accomplished most easily
and logically in Form_BeforeUpdate.  Otherwise, you'll have to write code
for each control AND Form_BeforeUpdate (just to be sure that your logic is
correct).  It seems you're just trying to dictate the order that they enter
the information....and that really shouldn't matter at all.  One person may
enter the data vertically, the next horizontally.  As long as ALL of the
entries are made and they make sense, so what?

The biggest issue I see here is that you have a poor design.  You're having
the user enter totals....when normal form would have them calculated
automatically.  You also appear to be storing them...another no no.  And
you're going to have a mess to validate here anyway...because a row total
may be incorrect while a column total is correct or vice versa.  Why
wouldn't you use a spreadsheet for this anyway?  I suspect you've left out
critical information from the data model shown...i.e., what does each row
actually represent?  Each column?  Is each row related to a date?  If so,
where are you storing that?