When exporting a pivot table to excel in Qlik Sense, the empty fields are exported with a '-' symbol.

When adding additional formulas to this excelsheet, like A1+B1 and this A1 field has a '-' value, excel returns #VALUE!.
(sum a1:b1 does work as a workaround). 

Is there a way to change this general dash symbol from '-' to an empty field. Preferable a general setting so I don't have to change all formulas?