I don't know, ask Mitsubishi. Maybe it's the same reason I get the deer in the headlights look 9/10 times when I go to the dealer parts counter and ask for filters for a Mirage cvt...
The last time I looked at a maintenance schedule it was a pretty generic thing that covered all Mitsubishi models except for the Lancer evo.
The lifters have to be replaced in order to adjust valve lash.