I'm not so sure. It would have made sense to make TIE Mark II available in Imperial Vets, but those clever people at FFG thought it would push more product if they remain available with the Punisher only, for the moment. Integrated Astromech seems like a similar case.
i bet one or two will come in rebel veteransIt is not about money, number of waves or related. It is about vital upgrade cards. Example : Integrated Astromech
Cost 0 upgrade quite critical to x wings. Something to fix it a little ok. You must buy T 70 blisters, Ok. It is a x wing fix in a x wing blister.
You open it and...ONE CARD. ONE. Perhaps you own many T 65, plus at least one T 70. Or more. And you buy a ship with ONE fix card. As I say very often, buy ships, not cards. But this is a little joke. Here your little fix. One per blister.
And the Tie / FO comes with TWO upgrade cards. Ohhhh man. Don't kid me.
Or, as the TIE Punisher came with two of the Mk II´s, they think there is enough saturation to face criticism if they pack them so soon after the first release.