I'm on the same program now, in the second week. From what I gather you're supposed to increase the weight at up to/ around 2.5% for each workout session. So, even though the reps are increased on day 2 from day 1, you still also should increase the weight.
Now, what I've done is that if I have an issue of not being able to increase the weight- limited on how much weight can be added - I simply try to increase the reps. In this case, if I have 8 reps to do, and cannot add weight, I simply do 10 reps. Is that acceptable ? I figured that if I do bench press with 45lb DB's, then after a week of increasing reps it would be then acceptable to start using 55lb DB's going back to starting with recommended reps and increasing them same way as the week before with the same weight. Not sure if this is good enough, but that's what I do.
If you can't do the same weight with higher reps on following workout day, then you probably started with a weight that's too heavy. If my approach is not acceptable, anyone, please advise.