Why no Size enhancement for ST?

[Captain Joy]

Originally Posted by JCurwen3

There is a Size limitation you can take to buy ST (and its subcomponents) more cheaply, at the rate of -10% per SM+1.

Why isn't there an equivalent enhancement of +10% per SM-1? To make it more costly to build tiny PCs with unrealistic ST.

As valid a question (?) is: why allow the discount for higher SM at all? Or, what is it about SM 0 that makes it the break point at which the cost of ST should suddenly (no longer) be dependent on SM.