Fixed asset SAP 9.0 Pl2 error

Hi!

The scenario as below:

1.Create Asset master data--> capitiliazation first with value=12.000--> capitiliazation second with quantity =2 --> Create sucessfull

2.  Create Asset master data--> capitiliazation first with value=12.000 --> check fixed asset master (open Depreciation tab)--> Capitialization second  with quantity=2 --> Error "Fixed asset "P8" not planned for quantity maintenance; remove the quantity"

I think that's error SAP  ?

That's SAP B1 PL9.0 PL2

Regards,

Hong Bich