Strategy tester of MT4 build 223 (erratic results - unreliable)

 
Strategy tester of MT4 build 223:
After loading 223 I got very erratic results with every run of the tester. I got profit factors as follows: 0.14, 0.55, 0.85, 1.20, 0.90. With version 222 I had pf=1.23 .
And all for a time period about 2006.10.1 -- 2007.10.1.
This is very unreliable to say the least.
Reason: