We used it this past deer season with good results. I buy it in West. 20% was $8.20 per 50 lbs. We also use their "Buck Blend" which is 50/50 mix of corn and 16% protein. It was $7.70 per 50 lbs.
PS If you buy it in West they close at noon on Saturdays.
Not trying to start anything, but 16% mixed 50-50 with corn is not going to do much for your deer unless you have an outstanding supply of natural groceries for them.
Right now, with the heat, unless you have had really good rains, you can expect your natural food sources to be steadily losing nutritional value until about Oct/Nov when it all becomes basically fiber.
Check the labels on the bags, whatever you are using vs big name brand stuff. The key to growth is as much (if not more so) in the mineral's percentages in the formula as it is in the percentage of protein.