Ah. I had suggested both of these factors in replying to another post discussing elevations.
I am interested in the relative effects of elevation. For example, most wargamers plop their batteries on top of the highest features available. That may be fine for producing range and for visibility (and hence is useful for bombardment). It also makes it more tiresome for attackers to approach the battery. However, such elevated positions create significant dead zones into which it is impossible to fire. Monhaupt and others write about the utility of horse artillery (and light guns in general) for counterbattery fire against such positions, by taking up a firing position within the dead zone and being able to fire upslope.
Batteries intended for defensive support relied on being able to damage enemy formations during their approach and on best effect of cannister at close range. For this purpose, elevation could be detrimental to obtaining the best possible field of fire.
I rather suspect that the first case you raise involves a French battery well sited for firing at a distance and a Russian battery sited for defense. In such circumstances the quote has nothing to do with relative capability of the pieces, though it is easy to think that at first reading. Do you have any other details about this?