Translation Results Requested Through Conyac Made Public

We are preparing to be ready to leave the Japan anytime after ○th, so there's no problem with the schedule. At this stage, we have recorded the lyrics in Japanese and French and we want to use whichever is best. Because time is limited this time, we are thinking that the easiest way to do it would be to get him to sing both the Japanese and French parts, decide on the spot the position of the vocals sung by A and the vocals sung by him, and then do a second mix in either Japan or Belgium. Would it be possible to deal with the studio costs by receiving a bill at a later date?