Does the lien expire or is it a one time fee? Also can those lien fees be added to what they owe us?
First, I am not sure what you mean by "Does the lien expire..." The fees to prepare, mail, and record a Mechanics Lien constitute costs that are paid once. A Mechanics Lien may not be extended or renewed like a Judgment Order. Mechanics Liens expire 2 years after the last day of work.
Second, as noted above, fees associated with the creation, mailing, and recording of a Mechanics Lien constitute "costs" for which you may seek reimbursement, but are not automatically incorporated by the Mechanics Lien Act.
I hope this information was helpful. Best of luck!