Yes, but what about the OP's original story, that he and his FC both played a provisional ball after having possibly played the original ball out out bounds. The OP found his ball in bounds, while the FC's ball was clearly out. Then when the OP went to pick up his provisional ball, the FC claimed that it was his, yet the OP was certain that the FC had hit a tree with his second ball. The FC refused to even look or consider the possibility, and claimed that the OP's provisional was his. The OP was able to show a bag full of balls, same brand and marked the same way, the FC was not. Does the FC get the benefit of a grave doubt, or is he required to actually go back and look for his ball near the tree? For the OP, it's just an abandoned provisional ball, so no effect on score. To the FC, it would be his ball in play lying 3, but he can't actually offer any evidence that it really is his.
This would be a matter for the committee to resolve having spoken to the players and any other witnesses.