dalton said: "Now such tickets for Mockingbird and Moulin Rouge run at least $250-500 for the cheapest off-center orchestra or mezzanine seats."
I can't speak to Moulin, but if you plan head, you can easily see Mockingbird for $169 or $199 (plus fees) from the side orchestra/side mezz.
It sounds like your beef isn't with the price, but the locations FOR that price, so you've hit the right approach for the wrong reasons. The reason to buy closer to (or on) the date is for when the show reduces previous premium seats to regular pricing. Some shows do it in advance based on the number of unsold premiums (in which case, you would still be buying online, but sitting centered and close) and some have to flip their last unsold premiums day of show.
I had been tracking Mockingbird, and the night before the show (I was looking at weekend matinees, specifically on Memorial Day weekend), after the night show started, they seemed to add $199 seats in the first through third rows on the side orchestra aisle. Unfortunately, I had two friends that wanted to go and they only released pairs, and not all at once, so we didn't buy two and hope more came later... but you can learn a show's ticketing rhythms pretty well if you get a bit OCD about checking in advance, specifically for the day of week and time you will want to go in the future.
That said, this strategy depends on people not buying all the $425 premium tickets. And, some shows, they just do buy them all... heh.