opps. Faulty memory. 74s were a few years back. Made me pull out a very dusty OM. At least on the 200, the manual states that once the gear is down, you should not attempt a go-around, 2E one side. It is possible, but VMCA2 comes into play, drag from retracting the gear, etc. would make it a not-so-sure thing and maybe having to trade altitude for airspeed, if you have it. I've done it many times in the sim (of course) and an 2E one-side approach is not to bad if it's not rushed and planned carefully for. Of course the 400 with more power is probably better, to a point.
Bottom line is a 2E approach one-side is a very undesirable thing. I guess Boing (and hence the company) thinks it's ok to continue on 3E, but personally I think it's a bad idea with possible damage to an engine.