I am just about to start running this on the press and having re-read the article I am a little puzzled on the day 4 weight.
The article states (my emphasis):
Take the ~90% weight you used for all the singles and perform two to three sets for reps to near failure.
So I am taking this to mean 90% of the multiple singles which we at about 90% of the relative max.
E.G. Say I have a max of 100 then I would have performed several singles with 90% of this weight. So when it says 90% of the singles are we talking 90% of the original max or 90% of the "weight you used for all the singles".
A little further on it mentions the weight 130 for reps, which in these examples is 90% of the relative max so that makes me think I have misunderstood this week:
Do a set of 130 pounds to NEAR failure