My doctor had a different procedure then that, giving 6 dilators its common (from all the girls i talked to who had him do SRS) within the first week after unpack to be at the largest one without much issue. One girl couldnt follow the procedure because she had complications but 4/5 including me didn't have dilation issues. As far as i know if you mess up once or twice (as long as time in between mess ups is long) you should be alright. Most healing happens in the first 3 months after surgery so those are more critical that you dont mess up your dilation routine.
My routine uses 6 dilators 16/16 size to 21/16 size (looks pretty scary first time i had to put this one in) x3 a day the first 3 months then x2 up to 6 months then 1/week if having regular sex, or 1/day or other day. Sessions last 35minutes per dilation, although i increase the time when i dont have pending issues giving more minutes to various dilators. Seems to have worked.
After unpack i was 4 inches, following instructions from my doctor I dropped to 3.5 inches (pre-regular dilation method), then left Thailand to go home and was able to regain my old depth (via regular dilation method instructed by doctor) and then some 4.5~5 inches on the larger dilators via regular dilation. The skin does stretch a little, and its important to use a lot of lube, and relax. Watch a movie / show, relax your mind, and thing go much easier.
I feel kinda sorry for those who have 2 ~ 4 dilators, i know if i skip one size and put in a larger one without stepping up normally... stings a bit.