Yes, it's pretty stupid that the R22 and 44 are somehow deemed to be trickier or more dangerous than the others in the class - still, if you want to do the check in the 120 it shouldn't be too hard to find a Grade 1 (or 2 now) working for someone with training on the AOC and endorsed on type who could do a review. I could put you in touch with one right now if you like.
The drawback would be if you wanted to fly the Robbies you'd also need to do an extra review in a 22, say, which doesn't make a hell of a lot of sense to my mind.
The 150 hour course would be an extra say $13 grand in a 22 over and above the 125 hour CAR 5 course if the last 30 hours weren't done in 3 months, so yes, certainly a greater expense. A 100 hour course from a Part 142 school, on the other hand, should save a few bucks (obviously only any good if you have the spare time and resources to do it all in one go).
I honestly don't think the new rules make it much harder for a flying school operating Robinsons and doing RPL / PPL / CPL, cost wise or complexity wise.
If you're looking for someone to do anything a bit more complex, particularly in this transitional stage, then it's certainly a different story and CASA themselves are about as confused as the rest of us regarding many of the new requirements. Hopefully it will sort itself out somewhat over the next year or two, but in the meantime where I work we're getting along not too differently from before.