I was actually thinking of the same thing when I finish my current cycle. If I used Wendler's 1RM formula on my last set of the day, I got a calculated 1RM 15-20 lbs greater than the 1RM I used at the start of the cycle. (my 100% 1RM, not the 90% used in workouts)
I think this is because I undershot my 1RM before I started the cycle. If you start with your correct 1RM for your cycle, then you only need to add the 5 or 10 lbs as Wendler says. However, if you are basing your numbers on a weight well under your 1RM, then you may need to recalculate it in order to start using the correct amount of weight.
For example, if you were using the 1RM of 175 for bench press to calculate your lifts, but your actual 1RM was 200, then you're not working with the same intensity that you could be. I would probably recalculate it so I start my next cycle were I should have been last cycle.
After writing that I checked my book. I just want to draw attention to page 8, "Starting Too Light" After reading that, I would say just add the 5 or 10 pounds and keep going as usual. Don't recalculate.