It seems the move here is to bet both decision and TKO/KO/DQ (Especially if you think a decision is unlikely)

For example,

-500 ML Mayweather - Bet 900 pays 180

-135 TKO/KO/DQ Mayweather - Bet 700 pays 518.13

+200 Decision Mayweather - Bet 200 pays 400

So if a decision happens you lose 300 and if a TKO/KO/DQ happens you win 318.13 on a 900 dollar bet.

So my question is what bets would ML Mayweather cover that the combo of Mayweather TKO/KO/DQ and Decision not cover? I think you lose with a draw on the latter two but it would be a push on a draw with bet on ML. Anything else?