Trying different feed brands can always be a good idea whether using FF or dry. That said, I can't imagine that one brand would cause a soupy mix and another not if using the same amount of water. Most feeds have a very similar blend of grains. I saved my analysis/ingredient labels from all the feeds I've bought. Looking at several of them now. They all start with ground corn, then in varying order they usually have soy, barley, oats, etc.. Some will have fish meal, porcine meal, alfalfa meal. After that, come the other nutrients - vitamins, minerals, additional proteins and fats. In spite of them being a varied blend, I can't imagine what would make one soupier than another.
I think the big variable is the age of the feed (processing date) and how finely ground the ingredients are.
My reply was a bit vague. I meant that the different brands ff was makeing the poops more solid versus softer/runny. Not necessarily the FF consistency itself. Although, there is a bit differing textures there too, but not much like you say.