My 360 build.

FWIW...... Getting the end weights for stock rods matched can be time consuming.
They will vary a fair amount. Checking 1 set of light SBM rods yielded bobweight variation of over 20 grams across the set if the piston and pin weights were all identical. So yes IMHO, lots of labor there.

And for info.... The rod end weighing part is the area most subject to errors.