Cool story bro, if it were a heavy it would be limited to 1 and it would exclude all other heavies from being called in. The Command Panther is classified as a heavy, for example, by relic. The KV 1 and Churchill is not, and if those were suddenly classified heavies, they would be getting nerfs, and not buffs.
Been a heavy doesn't mean it would put a limit to the amount of units you can build. The Cmd PV is limited to one due to been a Cmd unit.
Weight classification only matters in order to put certain units in different categories although their performance may vary.
It also doesn't matters what Relic calls it IMO (what's consistency), as like with language, if 90% of the people refer to something in a certain way, it's better for understanding to use the more common term.
Ex:
(This was written by someone no longer working on Relic)
Super Heavy Call in Vehicles (Tiger, Tiger Ace, Elefant, IS2, ISU, Jadgtiger, Sturmtiger, KV2)
Limited to having only 1 on the field
(This is by Kyle)
Wreck values normalized:
Ultra Lights 10/5
Lights 15/10
Mediums 20/25
Advanced Mediums 35/30
Heavies 50/40
Super Heavies 60/45
Panthers (command PV included), T3485, KV1, are advance premiums.
Tiger (TA included), KV8, KV2, Avre, Crocodile and Churchill are classified as heavy
KT is a super heavy.