Is this a correct arb?

[Bulbarainey]

LA @ Philadelphia
-115 Phil at SIA
+127 LA at matchbook

Is this the right way to do it? Put 115 on Phil do you would get 215, then 100 on match so you would get 227, either way you make 15 or 27$. edit: i see whats wrong in my math, betting 115 to win 100 and 100 to win 127, so then you would either break even or make $12? Is there something else I am missing? im a newb at this, thanks