Well, I made it 402.43 but let's not split hairs!
I couldn't open your link but managed to find your comments about minima in Part 97; very interesting. What I found more puzzling was that in Part 91 it prescribes the take off minima as not less than half a mile, for helicopters, which is quite restrictive if you are operating IFR.
I couldn't see any reference to approach bans, but did not have unlimited trawling time. Basically, when operating to ICAO Annex 6 or related rules, you cannot contine an approach below 1000 ft above the touch down elevation if the reported RVR is less than the published minimum. If you have passed that point and it falls, then you may continue (there are expanded bits to that definition, but not really relevant here).
I'm still curious about the additiona reference to 100 ft above TDZE bit, it seems to imply that you can decide to continue below the DA/DH if you can see the approach lights, but can't land from 100 ft if you can't see the required visual references on the airfield. What then? Missed approach? So you go from on instruments, to looking up at DH and 'going visual' (in real clag) commencing a deceleration, then at 100 ft you have to carry out a missed approach; back to instruments, re-adjust the aircraft attitude/power etc. Seems strange. At DH you can either see enough to land, or you can't, is the normal criteria.
Obviously there's always the odd chance you may inadvertently go IMC again below DH and carry out a missed approach (or the runway lights fail, as in the Gerona 757 crash) but normally it's pretty clear cut.