I not going to dispute your numbers. However, from my in game experience i can't help but feel volks proformance, especially in the early game, is pretty much on par with rifles.
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Imo problem lies elsewhere.
Grenadier where (and should be) the benchmark and not VGs. Riflemen where OP compared to grenadiers because of faction design since they had to carry the faction.
The early appearance of powerful units like Penal, Assault engineer, JLI, Pathfinder, Cav Riflemen, SP, ST44 VG and so on has made Riflemen seem weaker by comparison.
One should either reduce the power level available early or give powerful early units to all factions and that should include earlier access to PGs and Obers.