Custom WF function with a 0.00 cost is being differed by the workflow engine

Hello

I have done a custom function that is calling a PL/SQL function (which is submitting a concurrent program)
The cost is 0.00 but when the workflow is running, it differs the activity?

I found in the user guide that
If a function activity has a cost that exceeds the main threshold cost, the Workflow Engine marks that activity with a status of 'DEFERRED' in the workflow status tables and enqueues the deferred activity to a special queue for deferred activities.

I want to prevent the workflow engine from differing this activity because I do not want to wait for workflow background process to run.