Now my perf people tell me the one engine toga aint a regulation that the climb gradient is for all engine so i could use the lower DA.
To which your question should be "now what should be my strategy should I lose an engine during the approach or miss" ? Pray tell, what might be their answer ?
If the flight standards view is as you have suggested then it is grossly flawed. The underlying basis of heavy aircraft operation is a single failure at any stage of the flight being recoverable and that includes OEI during the miss.
I would opt for a higher minimum to satisfy the OEI consideration .. a lot cheaper than the fallout from a CFIT. However, to land involves putting yourself into the area where you have no miss capability OEI .. this gets back to inviolate commital heights .. and then what do you do if some idiot blocks the runway ? Then it comes back to very rapid risk assessment of what might give you the best outcome. If you are AEO, then the miss becomes attractive, OEI and you are between a rock and a hard place.
Some days it just doesn't pay to get out of bed.
Does your airline pay any attention to corporate risk management ?