Assigning Auto accounting rules for Labor cost clearnig account

We are on R12.1.1.

We have defined 2 sets of rules for deriving company segment. One is a constant value and one is parameter based.

In the Assign Autoaccount rules form, on the 'Segment Rule Pairing' block form, in the LOV for rule name, it only lists 'Constant' rule that we defined for the company segment and it did not list the parameter based rule that we defined.

Is this the intended functionality? Will the clearing account pick up only constants?

Please let me know if you need any more info.

Thanks