Did HTV have the same per episode budget as CBS-Digital had for season one?
I have no idea. I would wager adding a grain / noise layer over a CGI effect would be no more time consuming than waiting for the computer to render out a heavily DNR'd scene so they could slap an effect onto it.
From what I've seen of HTV's work in the past few weeks, this just seems to be the way they do things. DNR'ing films to death is their schtick. Despite having original members of the crew there to guide them, they lacked the overall skill sets required for a restoration of this magnitude.
As CBS knew when they hired them, they're not a VFX house. Sure, they can do it in a pinch but that sure doesn't mean they're good at it.
There are simply instances where you can throw tons of money at something and it will still come out looking poor if the skills aren't there.
CBS-D have worked hard to earn their stripes I think. I hope the next contracted FX company is as talented.