BAPI_CUSTOMER_GETDETAIL1 - why lastname = name

In module BAPI_CUSTOMER_GETDETAIL1 in subroutine ASSIGN_ADDR1_TO_ADDR2 is assigned:

" P_P_I_BAPIADDR2_01-LASTNAME = P_P_I_BAPIADDR1_01-NAME.
P_P_I_BAPIADDR2_01-FIRSTNAME = P_P_I_BAPIADDR1_01-NAME_2. "

This causes the swaps the name1 of the name2. Why is this and how this can be changed ?

Thanks.