If a line being 30% of the total means it's circled, then I'm thinking that teasing lines/totals that are 25-29.5% must have reasonable value? For instance, the vandy/kentucky game this weekend is at 29.5%.
The only way I'd imagine this is not a good value is if 30% is actually just a super precautionary measure with little evidence to suggest that betting fav/over at 30% is profitable...
Can anybody weigh in here?