To access the result from another Calculation Macro simply prefix the placeholder reference with the identifier of the macro like this:

${macro-id.formula-name}

All values of a formula can be accessed as defined in 

The macro allows to skip the Document Formula and only provide a Result Formula. This way a value can be calculated by the use of results previously calculated - either by a formula above in the table or by other instances of the Calculation Macro specified previously on the same page.

If no Document Formula is specified, the default results, like SUM or AVG are not present, because the formula does not iterate over the documents in the result set. Only the representation, the literal, and the result are provided.