I agree with the above post ...
that being said, you NEED to comb to the skin with a GOOD quality metal COMB not a pin brush a minimun of twice a day during blowing coat. The matts form in a nano-second, before your eyes. lol
These dogs are high matinence and if you can't keep up with the grooming during blowing coat, you really should have him shaved down, it's in the best interest of both of you.
After dealing with HOURS a DAY over the course of a couple of weeks of de-matting/grooming/obsessing during blowing coat, I finally had Tillie shaved down. Saved our relationship and my back! lol
I think the average blowing coat lasts 1-3 months...