Yeah so no scaling there.
It wouldn't be if Mark didn't just get hit by the paralyser gun, which clearly took effect in some way. He's also blatantly holding back, otherwise he'd fly through them easier than Oliver did. I'd say holding back to a certain level, as not kill them by accident and also not get ragdolled 10 times outta 10, when fighting would actually take a similar amount of concentration and effort than just exerting (close to) full strength. It's like balancing. It probably doesn't work linearly for Viltrumites - like I don't think they'd be hard pressed in lowering themselves down enough to tap on a table like a person or sth, they could probably use the same perceived effort in doing that. It likely gets harder when exerting levels of super strength that are still strong, but nowhere near their upper limits. In cases like these,
the handbook statement works well.
I think it sort of makes sense, if you consider Immortal being a smidge above S2E1 Mark in strength/maybe durability (if we equate S2 opening versions to main, which I think is fine).
Seems Mark only ever utilises super-speed in the most serious occasions, like against Reanimen once the frequency was blocked. Even then, he seemed to use it sparingly. Maybe usage of powers in these ways count as "skill" for Viltrumites. Like, instead martial art fighting style bs, skill could be referring to raw competence in using abilities like super-speed (specifically accelerated perception). It may take actual skill to utilise this more often, and could separate 2 Viltrumites with identical stats, including speed itself. We honestly don't know the nuances of having biology like this. We know these guys can f..k humans, feel, not crush them. A blanket assumption would be they shouldn't at all detect any nerve feeling from stuff this weak in proportion to them, no? But they do, and they'd probably feel a human's punch too in this case. Maybe they'd actually feel slight pain from a city level attack, but feel equal amount of minor pain from a country-busting attack. Who knows? Same would go for super-speed - using speed is like exerting a muslce; and no one knows how it'd feel like to "turn on" super-speed perception, since they don't have Red Rush-type 24/7 super-speed. Went off on a bit of tangent there, but eh. Very curious.