It will be interesting to see what they do with other vehicles, the current ones are common enough that 6 is a fair number to want. But it still limits you to multiples of 6 tanks.
Looking at the sprues they are 2 vehicles to a sprue, so there is an option to offer different quantities, or to offer a mixed support pack. But the big problem with WWII is there is such a variety of kit needed. And if these are true 1/144 scale then they won't mix that well with most of the existing 10mm stuff that is 1/150th to 1/160th in size.