I get the point of the payout, as more skilled players have a chance to get some extra units even if item luck means they don’t end up in first place.
However, in practice, it seems like worse players end up getting the faster lap times, as lower placement results in getting more boost items to help catch players up with the higher-placing players, resulting in lower lap times. In a couple of games I played, I was one of the worse players, but ended up getting the payout consistently due to moon power + melons.
Just something to consider and possibly tweak, depending on what the intentions of the payout were.