RL = run line? Not sure why that matters as +120 is +120 whether it is a run line bet or dogfighting.
But if you win a +120 for $100 then that would be +120. You don't count the amount you risked in the + column.
You won $120, therefore +120 is how you would track it.
Otherwise if you go 10-10 you're gonna be +2200 on the wins and -1000 on the losses when you're only up 200 bucks.