The solutions from the provided link should also be working within a variable. But you shouldn't start with the variable else doing the same step by step approach like in the link. Means creating a table-chart and applying there the accumulation step by step and if this worked you may transferring it to a higher granular table by applying the aggr(). The final step is then to adjust the aggr() dimension to the needed dimensionality and/or to wrap the aggr() with another aggr().
