Balance Sheet account can be posted to WBS in S4 HANA 1709

In my company implemented S4 HANA 1709. I found that it is possible to post to "Balance Sheet" GL account type in combination with regular (not statistical) WBS element.There is any Cost Element category assigned to this BS GL account. AVC control done using FM module.

How is it possible to post CO Cost Object WBS to GL account without any Cost Element Category assigned?