The moment at which to retard the thrust levers depends on several factors, specially your sink rate. The more the sink rate, the later you retard.
However, if you hear RETARD RETARD 3 or 4 times as the first post says, then the sink rate did not justify the delay in retarding at all.
You delay retarding when you hear the RA callouts very quick fiftfortythertwentten… Oops, flare some more and don't retard just jet (watch your pitch) then accept a somewhat harder landing and retard before touch down.
Floating and floating with thrust still on with RETARD RETARD repeatedly, I have seen many times. It is annoying indeed, and you eat up runway meters very quick. A BAD "technique" probably resulting from a previous traumatising hard landing.