I’m not trying to say the current system is good or your point is invalid, but that’s just simply not true for the context (VA refund policy) here.The price you paid, minus whatever the cost of a full flex economy ticket is on the day of departure = your refund.
As people have mentioned VA does calculate the refund based on the lowest Choice (not flex) fare on the day of the ticket purchase. I’d argue that’s actually a fair methodology.