I can only speak for a few operators, so don't shoot the messenger here. A number of operators do not use an AH at all and instead rely on the ASA or AFDS annunciator (B777) to display LAND3. As long as LAND3 is shown your good for the CAT3B Autoland. Now shoud there be a reversion to LAND2 (Fail Passive), they simply select the preset 50' DH on the RA and press on to a CAT3A (Fail Passive) autoland. This action is part of the briefing and set-up prior to conducting the approach.
Just because your experience is something other than that as described, does not mean it's unsafe, unapproved, or what ever. I think I know something about this subject BTW.
Each operator, depending on equipment, decides on a procedure that is factory approved along with regulatory approvals. They do not simply make this stuff up on their own. The 200' AH is simply a point of reference and is almost always lowered to something below 100' and 50' is most common these days.