so a magikarp_91 could turn out to be pretty good then?
Actually, I would believe its worth it because farming magikarp (or anything really) is super easy with Pokefarmer, and with some patience it wouldn't be too long till its fully upgraded. imo (i do, understand your logic too)I think you rather want to find a ballance with the CP/IV.
Its not worth powering up a 100IV magikarp with 10 CP IMO.