Collection costs would be added to what the person owes, I would think. In the OP's case at least, I'd ask the judge to include that in the judgement, given that the customer has already demonstrated a reluctance to pay.
You would have to sue again, in small claims court, for recovery of the fees.
The court will not preemptively award estimated collection fees since you have not yet been burdened by them and they are unknown. It's not like a regular civil case where attorney's fees are known by time you are receiving judgement.
It's an open and shut case to get a judgement in your favor on recovery of the fees. Just anticipate two small claims court appearances (or maybe recursive appearances if they don't pay the recovery fees) and it will be fine. Eventually they will just pay.
The court will not preemptively award estimated collection fees since you have not yet been burdened by them and they are unknown. It's not like a regular civil case where attorney's fees are known by time you are receiving judgement.