Getting a good number indirectly

Yesterday, I was looking around for the Game 5 money line in the San Antonio - Utah series. I wanted to put a small bet on San Antonio. As I checked the money lines, they were roughly +320 (on Utah) / -350 (on San Antonio). I was not thrilled by this price and I could not find any mid-market prices. In particular, I would have been happy to find a book offering San Antonio at -340 or -330 so I did not have to pay full vig. I was close to being forced to make a decision on whether to take -350 or pass, until I saw this Exact Series Line at one book that had +320 / -360 as their money line on the game:

San Antonio to win the series in 5 games: -320

Aha! Here was the perfect bet for me. It allowed me to get exposure on the side I wanted (the Spurs in the money line) and it allowed me to get a super price. The limit on the prop was much smaller than their limit on a regular money line, but since I only wanted to make a small wager, the reduced limit didn't bother me. The book would have been happy to make this bet as they were offering Utah +320 in the money line. Although this bet was in a prop category, it is exactly the same thing as the money line in Game 5 since the Spurs are up 3-1. The sportsbook likely overlooked this fact and in effect, they were dealing a no-vig line by offering Utah +320 and San Antonio -320 in two differently phrased bets.

The bet may not win, but I'm sure I had positive EV in making the bet.