BEx-Excel local formula ignores reverse sign from query display?

Dear Experts,

I'm experiencing a special behavior of BEx-Analyzer-Excel local formulas in combination with query structure element display.

In the Cube there are the values:

                            KFG 1          KFG 2
Query Structure Elmnt A     100            -200
Query Structure Elmnt B     -50            60

In the query definition the structure element for KFG 1 has the display "reverse sign", so it shows

                            KFG 1          KFG 2
Query Structure Elmnt A     -100          -200
Query Structure Elmnt B     50            60

Now I want to insert a BEx-Excel local formula with A + B.
I'm expecting:

                            KFG 1          KFG 2
Query Structure Elmnt A     -100          -200
Query Structure Elmnt B     50            60
Local BEx formula A+B       -50           -140

But instead it shows:

                            KFG 1          KFG 2
Query Structure Elmnt A     -100          -200
Query Structure Elmnt B     50            60
Local BEx formula A+B       50           -140

It seems to me, that the local formula in rows ignores the display behavior from query structure elements in columns.

Is that correct?
Any suggestions how to come around this? (I want to leave the query untouched, as it is widely used.)

Best regards
Gregor