"Bulking" is not necessary for muscular growth. Anything 15-20lbs (20lbs is pushing it) over competition weight would add very little if anything to enhance muscular growth.
Gaining fat isn't necessary at all, other than getting out of the single digit bodyfat so you don't lose muscle if you miss a meal etc. and of course you gain water back. The reason is, body adjusts consumption when it senses it needs to build muscle, and with those extra calories you can build muscle, and no fat gained. Some people just don't get this.

They talk about some universal constants or something, that energy can't come from nowhere yada yada yada...
