ASX Haze Visibility Issue

The haze effect I have been experiencing appears to be an intermitant problem. Without changing any settings, or weather changes for that matter, I get two different views. So based on a commmercial utility review-see web address http://www.avsim.com/pages/0707/ASX/ASX.pdf, I tried adjusting the visibility sliders to reduce the haze effect and determined that any adjustments had no impact. When I set both maximum visibities to zero I was expecting a fogged in scenario but nothing, and setting both to the max didn't give any further sight distance or clarity either.Interestingly enough, I downloaded and installed FSUICP 4 yesterday and since then I have not had any haze effect and views on the ground and at 35,000ft look crisp. Go figure. Any insight would be appreciated.Sincerely,John