Unfortunately nothing is that easy or simple.

Are we using TAB price, Bookie Prices or Betfair prices to gauge the 6-9.90 band? Prices @ close to starting time, 5 minutes out, 10 minutes out? What if we lay one and it firms to less than 6 or drifts to longer than 9.90? What if we don't lay one, and just before they jump it drifts into the lay band, or firms into the lay band?

Good luck whatever you decide.