FE Hoppy, it seems you've answered your own question. Perhaps rereading the alternative methods will help. Let's consider a practical example Zurich ILS 16 CAT I approach, shall we? If you chose DA of 1590 your required MA CG is 5%, isn't it? As we saw it earlier you must be able to fly it in EO conditions, don't you? My questions is: are you gonna follow published MA in case of SE GA at DA assuming A320 performance data? Will you fly published MA in case of a GA from 100 ft AAL as well?
I think you're missing the point.
OPS 1.510 covers the missed approach requirements including the need to satisfy the published climb gradient when above 2.5% or a minimum of 2.5% when the DH is below 200'. But, in both cases the procedures assume the GA begins at or above the published minima.
The case under discussion is that of a single engine landing climb from below minimum. As described in 17 item 3 of FDRs post above. The FAA have been very clear with their guidance so this thread is closed from an FAA operators point of view and I thank FDR for the excellent post. However, the EASA EU perspective is still open as there is no equivalent guidance in the EU references given thus far.