Barny, with your systems - out of interest:

Obviously they make a profit long term 12 years.

Does the system/s make a profit each year of testing?

The reason I ask is I see a lot of systems making profit for say a period 2006 to 2012. But when tested between 1999 to 2005 the results aren't very good.

This can either mean one of two things -
a. the system is backfiltered over a good period of time (6yrs) and could turn into a loss if used into the future
b. or racing has seen a change and punters are betting differently in the second period of testing and hence - the POT may continue.

PS: During the period of testing for 2006 to 2012 - each year saw a profit not just a large profit one year and small loss the following year.

Whats your thoughts and others?