I still want to retest the hypothesis but suffice to say, the splashing method of aeration is PROBABLY good enough to get reasonable attenuation as long as you use dry yeast or a starter with liquid. Doing nothing at all is worse and is likely to have a fizzled ferment. O2 injection ensures max attenuation all other things being equal.
In most cases, you won't really care about the detailed variables because your cell count is already high enough. In case you care, the oxygen level in the wort determines whether the yeast reproduce first (high O2) or go right to fermenting (low 02). With dry yeast, properly hydrated in water first, you probably have enough cells, or close to it, to go the distance.