It is OK to float.
It is OK to float.
Agree with Satch- I float a couple inches off my chest.
Video or pic would help to make sure everything else is good. Above the chin seems pretty high...
It's dependent upon anthropometry. The varying lengths of your levers and attachment points of muscles dictate where your effective range of motion ends. While my lowest position in the press is floating, I could make the bar touch my chest. Is that extra ROM "effective?" No, because I have to compromise tension and/or position to achieve it.
YouTube
I had someone video me today
Here is a set of 5
Don't rush through the reps too much. Take a second to reset the bottom position before each rep. Focus on trying to bring your triceps closer to your lats, think tight armpit. Also doing full ROM chin ups with the bar getting as close to the pec/collar bone as possible, with the grip at shoulder width helped me get a lot more comfortable in this position.