Very similar to the old Ramping training, probably around the early 90's. Only thing being , if I remember right, never go to failure on any set. Which is a general rule of thumb that might benefit anyone working out with any style of training. The 4 times a week whole body workouts, with 21 sets, may be a little overkill but the Golden Rule of BB'ing still seems to be, "if it works for you, it works for you". Just my view, but I would do the whole body thing on a 9 day cycle.
As far as the gains are gains thing, not so much true. We all are looking for permanent or lasting gains. If forced to take 2 weeks, or longer, off from working out and you find yourself losing a lot of muscle size and strength, than you have not been working out correctly in the first place. The false pump type of training can do this: volume training. Not against volume training, but this is usually the case.
Want to measure the arms first thing in the morning. Daily activities tend to give a natural pump during the day and do not suggest true muscle size. Using a thin steel tape, when getting out of bed in the morning, will always give a truer reading to arm size. Or anywhere else. Good Luck.