
What you can't do is compare the protein content of wet food (80% or more water) with dry food (less than 10% water). In order to compare correctly you would have to reduce both to dry matter and multiply the values into this.
For arguments sake If Protein of wet food is 10% and only 20% is dry matter, that actually makes the dry matter protein 50%, the food that is 90% dry matter and 25% protein actually gives you less protein (30.6%) than in the wet.
What many people have found when saying the dry food is to high in protein is that for some dogs the processed protein causes them problems. Why this is I am unsure, maybe it is to do with protein quality, freshness etc.