Ok, I think I've confirmed both (not many tests but perhaps sufficient assuming there's not other hidden factors at play other than trailing numbers).
So the only part of the comment on the help page was that it wasn't clear that bankers rounding took into account trailing numbers. I guess an example like 1.25 -> 1.2 (1dp) but 1.251 -> 1.3 (1dp) would take care of that. Right?
And now I'll delve into the differences between
dispdp, dispsf, significantfigures, decimalplaces and displaydp. Somewhere here I should get what I want surely! 