Do you mean: count and total up the individual entries across several records? (xAs, yBs, zCs etc?)
Yes.. Record 1 might have only A checked; Record 2, A and C; Record 3, B and D, Record 4, A and E. I want to get the correct total across those four records that value A occurred three times.
Checkboxes are not the right tool when you need to report on the results - related records would be the right choice. One reason it's best to use records for things that are alike is that records can easily be organized into sets (found or related) and these sets in turn are easy to sort and aggregate.
If you have a single record with A and C checked, that single record cannot appear in both groups for A and for C since a single record can only appear in one place. You can of course use PatternCount() but changing the structure would be the best recommendation.
If you wish to count ALL records then you can create a self-join (required to see all records within a table) using X (Cartesian product operator). You would then create a calculation (result is number) with something like:
PatternCount ( List ( selfjoin::checkbox ) ; "A" )
You can also just perform a find for A then count your found set, write it to a variable, perform a find for B ... and so on.
If you must get your totals based upon FOUND SET then you will need to create a calculation (result is number) as: Self = "A"
This will return boolean true (1) and then a summary field which counts this calc.
Overall, changing structure is simplest and will prevent these issues in the future. :-)