turbo nozzle

Hey guys I've been doing a fair fit of pressure washing recently, and even though i shelled out £300 + for a Whirlaway surface cleaner i still mainly use the Lance that came with my pressure washer (evoSystems). I am thinking of getting a Turbo Nozzle for my lance, but my main problem is back...

Hope you can help me. I have problem with left striping after cleaning. I have tried to change the way of wand moving when cleaning, distance from surface but with no results. I am using Honda Gx 200 3000psi and 12 lpm with 030 nozzle. Any suggest what to change or what should I do? Pictures...