The ratings have been weighted by the number of holes in each round for years now. Players' round ratings are maintained in the database on a "per hole" basis. That is multiplied by the number of holes in each of the rounds being used to produce the new rating at each update. That's why someone trying to use their published round ratings to calculate their new rating might not get exactly the same number due to rounding errors.
Rater of the tossed arc.