CO11N: Activity quantity not calculated by formula defined in work center

Hello Gurus,

I create a production order which work center has four activities (Labor man, Energy, Overhead and mantaince). For all of them, its activity quantity are calculated by a formula. This formula is the total sum of the standard values (time set up 1, time setup 2, time setup3, time breakdown and time manufacturing).

The system calculates properly the plan activity quantity which are the same value for all activities (sum of five times). This is correct.

But when I confirm a production order using transaction CO11N, the system doesn't have the same bahaviour as the plan order, in the calculation of the quantity activity. In fact, the system ignores the formula which is defined in the work center and this formula has been used to calculate the cost plan of the order.

Please, can somebody help me?

Thanks in advance.

Vicente