Running Sum - Over All

[A Hopper]

On a report I have a text box "MasterCartonQty" a text
Box "TotalCarton" and a text box "CartonCount". I want to
count only the full cartons. I have used the following as
the control source for "CartonCount".

=IIf(Nz([TotalCarton])=Nz([MasterCartonQty]),1)

The Running Sum of "CartonCount" is set to Over All.

Result I am getting:

CartonCount MasterCartonQty TotalCarton
20 11
1 20 20
2 20 20
2 20 15
2 20 18
3 20 20
4 20 20
4 20 10
5 20 20

If the first "TotalCount" in the report is less than
the "MasterCartonQty", "CartonCount" is Null.
I would like the same result throughout the report.

CartonCount MasterCartonQty TotalCarton
20 11
1 20 20
2 20 20
20 15
20 18
3 20 20
4 20 20
20 10
5 20 20

There will be times when the "MasterCartonQty" will change
in the report. However, if the "TotalCarton" is equal to
the "MasterCartonQty" I want it to be counted.

Example:
CartonCount MasterCartonQty TotalCarton
20 11
1 20 20
2 20 20
3 6 6
20 18
4 20 20
6 2
20 10
5 20 20


At the end of the report I would like to get a sum of all
full cartons the various "MasterCartonQty" full cartons.
Since I will not know how many different "MasterCartonQty"
there will be on a report I am not certain how to set this
up. I would like to avoid running seperate reports if
possible.

Full Cartons = 5
MasterCartonQty 20 = 4
MasterCartonQty 6 = 1
MasterCartonQty ? =

Thanks for your help.

Allan