That's certainly a better way of expressing it. However, I suspect that for many people the overall time would not be similar, but almost double - because digging out the information out the information in the first place often takes more time than entering it. Also, when you come to enter the other family members you've either got to locate the relevant head of household on your My Ancestors page or type in the census references and surname again, either of which takes time.
Once you've got the information in front of you it's possible to enter between 150-200 relatives in an hour (or more if you can type properly and not with two fingers like I do). For the average member with between 1000 and 2000 relatives on their tree (and therefore between 200 and 350 relatives on the the 1881 Census) imputing the whole lot in one go is only going to take an hour or two - so it hardly seems worth messing around.
But for someone who is running a One-Name Study, or who has a much larger tree, the two-stage process might be worth considering.