I find it strange as well, especially with buying a built head. If the thing comes to you assembled, you shouldn't have to disassemble, correct, and reassemble to use. But oh well I guess that's just the game.
Folks buy a new carb, they don't tare it limb from limb gauging everything, and that's a 400 dollar carb. Guys pay 1500 bucks for heads and have to disassemble and measure. I wish Eddy and EQ could read my post right here, and give me an answer