Well, there's definitely fuzziness in encounter points. I mean, an encounter point rating is literally just Level+10 for non-unique/hero/summoner characters. But some ability sets are definitely better than others, some demons work especially well together and have synergy in their capabilities, etc. There can also be more situational quirks, like running into demons that just happen to hit you or your party's weaknesses, and/or are resistant or immune to your preferred attacks. None of those sorts of things are taken into account for encounter point ratings... though in the case of the non-situational ones I do account for them when designing encounters (which is why this encounter is just 1 Oni, not 2, even though 2 should be allowed for Rush's Sanctum going strictly by their encounter point value.)
TLDR: Feel free to argue with encounter designs and offer feedback.
Though, yeah, in a case of 27 vs. 60, I will probably need a fair bit of convincing to apply a nerf hammer.