I completely disagree. 400 yards is MUCH harder than "2x 200 yards".
I can make shots all day every day on woodchucks at 200 yards. Easy. I'm angry if I miss at that distance. I can almost shoot them in the eye at 200. At 400 yards I'm lucky to hit the whole animal, never have actually.
Under "ideal", unchanging conditions, bipod, sandbag, no stress, no rush, my groups double in MOA between 200 and 400.
Going from "I can shoot 2" at 200 yards at the range, with sandbag and a shooting table under cover, with no pressure and no rush." to shooting at an animal at 400 yards that might leave at any second, using a tree branch for a rest, judging wind across a valley, with my heart pounding...
No, I consider that poor judgement, at best.
Well, if you throw enough stuff in there that I didn't say I'm sure you will be correct.
I assume he is bright enough to know that the conditions he is shooting in will need to be the same for different ranges to make a comparison.
If he can't shoot but a 10 inch group at 200 yards I bet he can figure the rest of it out.
I can shoot a better group proportionately at 400 yards than I can at 200 most of the time depending on the wind.