Newbie: Check my pointspread arb calculation

[gotme]

Team 1 -3.5(-115)
Team 2 +3.5(-105)

If I were getting a 10% bonus on both accounts.
If I were to place an even bet of say $300 on each team:

Team 1 wins: Win 255, lose 300, bonus 60 = 315 = $15 profit
Team 2 wins: Win 285, lose 300, bonus 60 = 330 = $30 profit

Am I getting this correct? Am I able to lose this bet at all?

Thanks.