Right,
the R22 was originally designed without the governor so the blades were kept light to enable easy/quick control of RRPM using the throttle. As already said this does lead to rapid loss of RRPM on engine failure. I can't say much on the subject of 1.5 1.2 secs as this does depend on pitch angle due density and weight.
It also depends on Kinetic energy available to convert in to restoring RRPM. If you have 102kts of K energy very little flare is required compared to K of 60. In fact trying to convert IAS of 30kts or less is fairly inaffective in the R22.
As for height lost - if you were to flare enough to counteract the descent due to lever down, over that short period of time no height would be lost.
As you know you should have 65kts of K energy and RRPM 97-110% to covert before commencing the flare.
Does that answer your question?