Given the same effort, promises, attention and preferences, a C+ team is generally on the cusp of signing range against an A+ (not a high A+, though). He may be listed at high, but if everything else is truly equal, that high is very low. A little extra effort from the A+, if there’s any left to give, would likely push that C+ to moderate.
The prestige range is, I suspect, just a hair under 2 full prestige grades; meaning, given absolutely identical circumstances, effort, promises, etc, a team 2 full grades down is going to be “on the cusp” of slipping in to signing range, where they’ll have something like a 1 in 4or5 shot at the guy. Some C+ will make it, some will not, that’s my impression after lots of battle analyses throughout 3.0, including beta. It might be a little under 2 full grades. I’m confident it is not more than 2 full grades. So no, given the same circumstances, I would not expect any C- team to be able to get into signing range, while some C+ teams may.