Betsy,

When you are talking about using code on the After Update event, it
seems to me from what you have told us so far that you are about the
After Update event of a control on the subform1 subform... am I right?
If so, the syntax Me![subform1] will be wrong, because "Me" already
refers to subform1, and subform1 doesn't have a subform named
subform1... if you catch my drift.  Anyway, I may be off track here,
because I can't quite understand what you are trying to do, and I can't
see the point of allocating the value of a control on a form or subform
to another control on the form or subform.

If by "school form will have a subform for each month" you mean you will
have separate subforms for each month, then this would also, on the face
of it, seem to be a bad idea.

Maybe this will help...  You can put an unbound textbox on the main
form, and in the Control Source enter the equivalent of this:
=[subform1]![tot ref]

And if you had 2 subforms, each with a [tot ref] control, then you can
do like this in the textbox on the main form:
=[subform1]![tot ref]+[subform2]![tot ref]

In other words, if I get the gist of what you want, then using code is
probably not applicable.