Minimum Flap Retraction Altitude is the altitude at which you accelerate and clean up after an engine failure. e.g. 1000'agl.
Acceleration altitude is the altitude at which you accelerate and clean up after a normal take-off, e.g. 3000'agl.
Somewhat close, but no cigar.
If we look back in time, we find that the MFRA is a certification standard, from CAR4b, and on piston, turbopropeller and early jet transports, was/is 400 feet AGL...or, more correctly, the runway surface elevation.
However, certain airfields with obstructions off the end of the runway, have a higher MFRA, dependant on the elevation of the obstacle.
In certain cases, a turn to avoid the obstruction can result in a lower MFRA, however in no case can it be lower than 400 feet AGL -or- that altitude specified during certification of the aircraft, as demonstrated by the manufacturer.
Now, looking at normal operating practices used by airlines, the normal flap retraction altitude can be an altitude dependant on the preference of the airline -or- that altitude required by noise abatement procedures for the particular airfield.
As can be seen in the second situation, like many things in commercial aviation...it depends on several variables.