It's not that one helicopter is safer than another to hover OGE - it's that hovering at 50 -100' is not the same as hovering at 500 -1000' - all the hover references are much further away making precise control more difficult.
Because the hover references are further away it is much easier to end up flying backwards or sideways without realising it and whilst an R22 may have enough power to hover OGE, there isn't much left for manoeuvering and an inadvertant descent usually follows. A normal hover scan doesn't usually include the VSI (RCDI) but this is vital in high hovering.
We do a lot of high hovering (500 to 1500') for FLIR searches and having an aircraft with a dopplermeter (hovermeter), a decent stab and a bar alt/rad alt hold makes it much easier. Doing the same thing in an R22 without any of the above is more difficult, especially if you haven't practised it before.