I believe the difference between what you are seeing with your profiles and other remodelers who are listed in two categories is that the latter are likely in the paid advertising program. These folks likely have only one profile, but are paying to be listed in additional categories. Since they only have one profile, the reviews/photos/comments/etc. would be the same in both.

It looks from this end as if you created two separate profiles, one under design/build and one under kitchens and baths. While this certainly helps you show up in both categories, I believe they are then treated as separate profiles and thus reviews would have to be solicited in both. If this is the case (you have two separate profiles), an option may be to pick one category and combine the profiles (Houzz support should be able to combine the profiles for you). While it takes you out of one category listing, it will strengthen your single listing, save double the work, and help you bring your listing higher in the Find a Pro section.

Not sure if this helps, but good luck!