sorting problem

[curiousfellow]

In a pivot table I have three dimensions and one calculated value.

First dimension is sorted by a string value within my table.The second and third dimension should be sorted by the value of the expression.

I tried to use the expression as a sorting expression of the third and second dimension. I don't get the correct sorting.

Alternatives like aggr and ranking did not give the correct results either.

In the soring tab it is not possible to demote or promote the dimensions 

Using the Y-value  affects the sorting of the first dimension too.

How to solve this ?