Pellets have never been proven to be perfect for our fids. The company will tell you that theirs is the best diet to get you to use it. All the experienced and expert bird owners I know of will tell you a fresh food diet is best supplimented with pellets, not the opposite way around 
The Harrison's web site did have some "studies" which showed their product better than seeds (by measuring the health of CAGs, and comparing the ideal blood levels of both those on a seed and a Harrison's diet ). I don't know if they could do a study with a primarily "fresh food diet" that would be replicable by everyone.
That said, I understand what you are saying. However, if I "supplement with pellets" Wuzzie will probably never eat them. When I say she is "converted to pellets" I meant to say "After all other food is gone and she is
absolutely certain she won't be able to bum any more food off us, then she eats them." Today she held out till 7:30 pm. then ate 20 pellets in 45 minutes!
Although they are different animals of a much shorter life span, when I worked with lab rats 20-30 years ago, all we ever fed them was Purina Lab Chow. The rats, which certainly can eat a variety of foods, were always in great health.
That said, about 20 years ago at work we had a Mynah bird on a pure pellet diet. Can't remember what it was, but it didn't work: I took the bird to an avian vet and he put the bird on a "brown rice-grapes-and-canned-cat food diet." The bird immediately recovered and lived many years longer.
Just curious if anyone actually would follow Harrison's advice.
Tomorrow I take Wuzzie to the avian vet that helped me with the mynah long ago, and I'll see what he says.
He does sell Harrison's at his clinic.
