BPC Script Logic - account mapping deliver wrong result

Hi,

I want to perform a simple account mapping / Transformation. I have maintained my source accounts (Attribute A2003A2) and targets accounts (Attribute A2003A1) as attributes value in account Dimension (see Appendix "Master data"). Is it possible to map the accounts via script logic?

My script seems to be faulty and processing time is very long. Is there improvement?