My ringneck is such a sweet bird but he's also quite moody with his biting. 50% of the time he'll let me scratch him, pat him and like it, the other 50% of the time he attacks

He really hates being on the floor, and the pet shop i bought him from clipped his wings so i guess thats why he hates the floor. But the question i have is: every time he bites me hard and it hurts, I say NO and put him on the floor. because he hates that and he knows the only way he's getting up off the floor is by stepping up on my finger... is that a good idea? or will that cause problems later on? He's no where near 6 months of age so i know its not bluffing.
He loves his cage (and can be a bit possessive of it actually) so I don't want to put him in his cage when he's been naughty, he'll probably see that as a reward. I just want to know if you guys think I'm doing the right thing or not.