I accept that we now have the A109 and AW109 type ratings, the former covering the A, AII, C, K2 and LUH variants, the latter covering the E, S and SP variants. I have never suggested otherwise
I do not accept that "each variant will be a separate type rating" as hueyracer would have us believe, as that would suggest that to go from, say, the C to a K2, or an E to a S would require a type rating course to be conducted under the auspices of an ATO followed by a skill test. On the other hand, to go from a C to an E would clearly require such training and testing.
And there is no such thing as a differences check. Where applicable, differences training will be carried out but this does not amount to a check.