Auto AC cross charged TXV, why different SH vs P curves?

[AliXV]

I have two block style TXVs from Japanese-style Kei cars.
They look visually identical but they have two different control charges.
Both cars come with the same evaporator, same engine displacement, both 1.2-1.3L petrol engines.
One of them has a tiny 70/100cc fixed displacement Seiko Seiki vane compressor, the other has a bigger 125cc max displacement variable swashplate Delphi CVC comp.
The TXV for the former (vane) seems to have a higher MOP setting and generally speaking seems to flow less refrigerant in the evaporator since it fully closes after cooling the power head with freeze spray and takes a short while to reopen again, while the other TXV (variable displacement comp) only throttles a bit even with a frozen power head, and takes a longer while to open wider, so overall it seems to flow more refrigerant and has a higher MOP.

After further research i found that, basically, auto TXVs all belong to the cross charged type and all go 0 superheat at low heat loads since they're designed to be still open around 32F evap temp, however according to the compressor type they provide around 5K or 10K superheat at higher heat loads and accordingly different refrigerant flows.

Vane compressors-10K "hot"
Fixed displacement swashplate-10K hot on small displacement engines, 5K hot on V8s and the like
Variable displacement piston-Nearly always 5K hot except few exceptions (some Toyota Corollas, early Scion Xbs and Scion Xas)
Scroll-Indifferently 5K or 10K hot

I understand more superheat means less efficient evaporator's cooling capacity usage, so i think using a 10K instead of a 5K might mean the AC would take longer to cool.

Any other possible reasons? Smaller compressors aren't meant to pump too much refrigerant perhaps?
Too much engine load on small engines and fixed displacement comps? Too little refrigerant flowing through a cold evap might possibly mean unstable compressor displacement control with variable compressors?

Thanks