First, it's an average - a special one - but not a handicap.
The answer is no as far as ranked rounds are concerned. For average calculation, a score is a score, no different weights. 9 hole scores double for this purpose.
Alas, tournaments provide twice the basic number of XPs => you'd level up quicker.
Note: Practice rounds count towards levels but not towards average.
Note2: Same for Par3 and Par5 rounds, ranked and practice.