I've been trying to figure out why TMT and AVL appear to be...

I've been trying to figure out why TMT and AVL appear to be under different levels of scrutiny by the EPA
Look at their respective EPA referrals:
AVL:

TMT:

EPA determination letters:
AVL:

TMT:


I don't know how the process works, but to me it appears AVL hit the EPA with more information up front at the referral stage and are being assessed on that information with some additional info required. "The EPA considers there to be sufficient information to undertake assessment on referral information".

TMT were issued with an environmental scoping document after receiving more public submissions, with further studies required. TMT changed the parameters of their proposal May 2021.

So it doesn't appear to be a case of first here, but of best dressed.