I just read your first Post here PartyPooper.
You said these 21 Bets were Overlays.

You have worked out level stakes and got an answer.
Then you worked out Betting to Prices and got a different , more rewarding answer.

When you bet to Prices, these prices you say, are they the Final Dividend Prices, or are they the Prices you calculated prior to the event to establish whether the animal was an Overlay.

If they were based on Final Dividends, then do a further exercise using betting to Prices, but this time substitute your calculated Prices and Percentages as the wager, but of course using the Final Dividend as the return.