I think it depens on the verbal agreement you do with the client, i mean you could go both ways ans say like: Oh yeah i can work your tracks maybe at an extra charge?... or like: yeah no prob i´ll do it. I don´t think there are any rules about it, specially here in a freelancer´s platform where competition is SO tough, i mean there will be less experienced and less professional people that will put all the production they can to get the job, so it´s complicated, i suggest you be the professional you are and charge for whatever you think it should be charged for the work you do, if you dont get the job... well then it probably wasn´t a good client.
BTW, there are no stupid questions! XD
