Hi Tan,
OBY7 is used for create a chart of accounts with reference of another chart of accounts. But FS15 is used to copy GL account master at co.code level and If source and target company codes are in different SAP systems, then the program writes a sequential file. This file can be imported by program RFBISA20 and t.code FS16, which transfers the master data into the target company codes. In this case, the target company codes are specified when you call up program RFBISA20. If source and target company code are in the same SAP system, the data transfer can also be carried out directly by program RFBISA10.
Regards,
Mukthar