Yes but, one thing: I follow the rule of not going to failure on the "+" sets but keeping at least 1 rep in the tank, and I don't take that into account in the formula when I try to reverse the weightxreps into an estimated 1RM.
So, say, if you get 4 reps on your 1+ set and you can honestly say that you had 1 more rep before failure, that somewhat compensates, right?
So far, the 1RM formula calculator has been pretty much right, I tested my 1RMs two weeks ago.
Got 58kg on OHP, then did 9 reps with 44kg, which equals to 57kg 1RM and at least 1 (possibly 2) reps in the tank.
Got 140kg in the deadlift using the belt, then did 8 reps with 108kg without belt which equals to something more than 136kg, still with at least 1 rep in the tank (probably that extra rep would have been without awesome form, due to the lack of belt).
Today I did push press, I'd estimate my 1RM at about 10% more than OHP (so 64-66kg give or take), I did 7 reps with 50kg, which projects to a 1RM of 62kg. This is the only one who's not in line with the estimated 1RM, but I was interrupted during the set, I had to rack the weight after 2 reps, then unrack it again for the following 5, and I feel it somewhat diminished my focus.
Since I'm in the very first week of the very first cycle, I should expect my estimated 1RMs to match the tested 1RMs, and then I'd start to see teh gainz from the following cycles, correct?