Actually, semi-smart designers make the spar cutout deeper when they wish to use that spar without having to taper it.

Furthermore, smart designers understand how sensible it is to taper a spar thickness and do the work necessary for optimum weight vs strength.

Personally, if I knew that a kit cutter didn't understand the value in following the plans as printed, I'd find another kit cutter. And I wouldn't use plans that had a spar that was just as thick at the tip as it was at the root on a tapered planform. But then I figure the model's performance is more important than doing the kitting at absolute minimum cost and effort.