Chinook ER purchase is only Tranche 1 of Chinook Capability Sustainment, by the way of what used to be 60 CHINOOK until recently.
38 are very old (albeit extensively upgraded) and past 11K flown hours. Of those 38, 9 are going without replacement, and 14 will be replaced by ER.
That means there are another 15 that are bound to require a solution in a non distant future.
The rest of the fleet is made up by the much younger HC5 (8x) and HC6 (14x).