The SE rate of climb of a PA34-200T (don't have the data for a 220T) at sea level is in the region of 200' per minute, at 4570 lbs (max T/O weight), gear up, flaps up, inop engine feathered. At 10,000' this is in the region of 140' per min at standard temp. SE ceiling is around 14,000'.
So its not always the case that a light twin won't climb on one engine, though the POH for the 200T states that a SE go-around "should be avoided if at all possible" and that under "some conditions of loading and density altitude a go-around may be impossible"....
I was always taught to commit myself to landing when at the FAF of a precision approach and the gear goes down, whether it is on a runway, taxyway or midfield, rather than go around. There is nothing wong with practicing asymetric landings all the way down so long as the 'simulated' engine failure is carried out with the throttle, and that if a go-around becomes nescessary then both throttles are used.
Cheers
EA