Hi hawjl
I'm not quite sure why the rounding of the published minima changed, from memory Aerad (as was) published the minima rounded up to the next 10ft until about 2011 and I think Jeppesen might have changed around the same time.
PANS-OPS ICAO Doc 8168 states: "Publication of OCA/H. An OCA and/or an OCH shall be published for each instrument approach and circling procedure. For non-precision approach procedures, either value shall be expressed in 5-m or 10-ft increments by rounding up as appropriate." I am not aware of (and can't find) any similar wording for precision approaches but I do wonder whether that wording from PANS-OPS, or a previous version of it, combined with traditional instrument displays, gave the initial impetus to the rounding up.
Personally, I can't recognise much less than 10 ft on analogue or EFIS displays so I have stuck to rounding up to the next 10.
Cheers
TeeS