Yep. Brady 'certifying' at 165 only means he is was between 157.1 and 165. If he so desires to go down to 157, that action will be governed by a decent plan. Certifying in no way fixes his weight at 165 for the season.
I will remain on an island and say his target is 157 despite the breadcrumbs we have been fed.
Given the relative strengths of the two weight classes and Edsel vs Negron's performances to date it seems Brady at 157 makes the most sense for potential team points.
The only reason to keep Brady up at 165 is if Brady himself doesn't want to do the decent. For all we know he was walking around at 175 a few weeks ago and has already had to cut to get down to 165. I don't think so, but it is possible.
It would be interesting to know his (Brady’s) thoughts.