. . . R22 covers all small piston helicopters . . .
Nope. It's all there in LASORS F8.4.
Section F Appendix C lists the Helicopter types. R22 / R22A / R22B are listed together but R44 is a separate type.
So R22 covers you
only for R22.
The only exceptions are the following types which are grouped together:
Bell 47, Brantly B2, Hughes 269, Enstrom ENF 28, Hiller UH12 . An LPC on any of these covers you for all, but you still have to have the 2 hours experience on each individual type. R22 is
not included.