For reference, I shot a spike last year. I process my own and refuse to grind anything that isn't red. I trim 100% of fat and connective tissue out before I grind. I then add 10% beef fat (ribeye) prior to grinding. My total weight for steaks, and burger was 161 pounds. We eat a lot of burger so only saved prime cuts for steaks. The largest bull I harvested put 255 pounds of meat in the freezer using the same processing method.
I have heard of many people through the years complaining about processors. In most cases, hunters don't have realistic expectations on how much they should get back. In some cases, I do think processors are careless during trimming. They get in a hurry as time is money to them. Bottom line, if you want high quality game on your table, do it yourself.