First of all, you need to look at those flakes again and examine the color. Dandruff flakes are white. On the other hand, the residue from styling products usually is not white and being sheerer in appearance.
Those flakes caused from a build up of styling products are better dealt with clarifying shampoo. You can even make your own as I mentioned in an earlier post just by adding one tablespoon of baking soda to two and a half tablespoons of your normal shampoo. This really does strip away all that gunk and leaves hair beautiful again.
Then again, you might be saddled with white dandruff flakes. In that case, you could also try crushing two aspirins (use only if you are not allergic to aspirin) and mixing them with the same amount of your normal shampoo. The reason this can help this problem is the fact that aspirins have salicylic acid, which is the same effective ingredient found in higher priced dandruff shampoos.
Try this advice because you have nothing to lose–only more beautiful hair to gain!