Questions regarding match load

[duvels]

I try to keep my first choice players fit throughout the season by rotating based on match load. You get a rough indication about the match load of a player from the past 14 days in 4 levels: light, medium, heavy and very heavy. You get some more info about this if you hoover above that heart icon which indicates the overall condition of the player. This info is: number of minutes played, number of matches played and average distance covered, all in the last 14 days. Now, how does this match load get determined?

For example: I have Brandon Williams with match load "medium", with 101 out of 180 minutes played, 2 games played and 7.0km covered on average.

On the other hand I have Marcus Rashford with match load "light". 2 out of those 3 stats are higher than Williams' stats: 132 out of 270 minutes played, 3 games and 6.9km covered on average, yet the match load is lower. Even the 3rd stat is higher if you take the absolute number of distance covered instead of the average number.

Am I missing something? Is the average distance covered the biggest factor here?