Lots of people are surprised to find out that parrots in the wild will often "comfort feed" their babies for up to 12 months!
The wild black cockatoos in Australia take absolutely ages to wean their babies completely. It's very funny to see these fully grown "babies" still begging for food from their parents.
I know lots of people share the opinion that companion parrots are weaned too early. It is simply not economical or desirable for the breeders (and customers) to take a year to wean their chicks. If this was the case then by the time a person go their parrot home they would be fully grown!
In other words; yes, it is perfectly normal for your Grey to still want some feedings.
Although he is eating other foods and doesn't really need
formula, he is still craving the comfort he got from being fed by his parents.
If you want you could give him a few comfort feedings and then wean him over a few months. You could give him one feeding a day, then taper it off to one feeding every second day, and so on.
Some people believe that handfeeding your own parrot is not a good idea. Parrots could associate you as their parent figure and then eventually reject you (because no-one wants to hang out with their parents for the rest of their life!
Others believe handfeeding your own parrot is the perfect way to build an even closer bond with them.
It is true that there are many, many parrot owners who have well-adjusted parrot companions that they handfed themselves.
I've never handfed my own birds (most of mine have been much older when I got them) but I thought I'd give you both views so that you can decide yourself.