Between meat and milk

peace
The Gemara states that there is no need to wait between milk and meat, but rather between meat and milk, but it does not explicitly explain the required period of time.
According to the Tosafot, it is possible to have two consecutive meals: one with meat, and the other with dairy. Mr. Ukba does not specify any time period, but is content with distinguishing between the meals.
Based on this, I don’t understand why a distinction should be made specifically between a meat meal and a dairy meal and not also between a dairy meal and a meat meal?