From Leaflet 14
Unless otherwise stated in the Pilot's
Operating Handbook or Flight
Manual, the HOT position should be
selected well before power is reduced
and retained to touchdown. On some
engine installations, to ensure better
engine response and to permit a
go-around to be initiated without
delay, it may be recommended that
the carb hot air be returned to COLD
at about 200/300 ft on finals.
m) Go-around or Touch and Go
The leaflet clearly says for carb heat to stay on until touchdown unless the POH specifically requires the carb heat off. Every carburated single engine Cessna POH says carb heat on for landing.
Some Pipers do have a note in the POH that cautions that "carb heat should not be on for approach and landing unless icing conditions are present"
Having carb heat on until 200 feet as a general practice regardless of conditions would be operating contrary to the POH. In any case if you have the carb heat on during an approach in a Piper because you are experiencing icing, it seems pretty silly to turn it off when you are still in the air.
Grumman POH's have a note in the before landing checklist that says "Carb Heat: As required, leave on if icing conditions exist"