No profit in laying?

[Alnicoll]

Hi
Could someone help me out here?
I've been using the software to scalp horses before the off. I use £2 stakes for back and lay. Always back high and lay low. Always break even.
What am I doing wrong?
Thanks

[gazuty]

Are you greening across the field or just leaving the green on one runner? If just one runner, then you are just flat on every other runner.