The increase in ketones after a meal of MCT might be indirect. That is the dietary fat goes into the energy pool.... reduces the bodies consumption of ketones... more AcAc and BHOB is converted into Acetone.... and acetone increases because it stops being metabolized when we eat more fat than our body is asking for.

So ketonix measures just one ketone, Acetone, a ketone that is not made directly from fat. Second ketones are a "difference" variable, that is a quantity that is the difference between two different processes, generation and consumption of ketones. So it's hard to say why, exactly, there are more or less.