Rule formula to get balance value

Summary:

In business rule, we need to get the balance value of an account skipping zero and missing.

Content (required):

The business rule needs to get the balance value (skipping zero and missing) of a balance account. The value must be the balance in each month as it is being calculated.

Have tried @RANGELASTVAL, but cannot get it to use a range/xrange with @CURRMBR. Need to be able to cross periods and years to get the latest value up to the month being calculated.

Also tried @PTD but this does not allow specifying the source account crossed with other dimensions.