There's no US code that would require that. Some facilties engineers like to include load information, and that's a great idea, but it's not required by US codes. I have no experience in Canada.
Adding up the horspowers and stating that total makes little sense to me, as that number is at best vague and at worst misleading. There's very little information to be gained from such a number outside of assistance in generating a crude estimate of full load amps. Such a number could NOT be used to size feeders, protection, etc., and therefore is almost useless.
Listing the individual motor sizes would make more sense to me. If you're inspector's cool with that, I'd provide that instead. But generally, I'd say put whatever nameplate he wants on there just to shut him up and keep him happy. Nameplates are cheap, and no-one should really trust such a nameplate anyway, but rather look at the motors or drawings to see what's really connected.