They cremated, which means every sample is worth 10 or more, if coming from close by and might represent individuals which being buried irregularly or assimilated by people which used inhumation. Obviously most of the samples will be from Cimmerians, Scythians and other foreigners, since the locals cremated. But there should be some in between, and they are, which is enough.
Because you won't find much more in the Bronze Age, much to the South of the Tisza zone. You forget that even a small number of samples from close to the cremating core groups is decisive. Especially if you don't get no multiple finds from relevant clades elsewhere, which proves they weren't anywhere else.