DX10 Fixer and any payware contrails addon?

[WallysWorld]

So I finally discovered Steve's magical DX10 Fixer last month and been loving it since, but I find that installing any payware addon that adds more extensive contrails like Envtex or PrecipitFX causes a weird stuttering issue. The issue is not directly with the contrails themselves, but weirdly when flying high enough to get the contrails and then looking down at the ground from the plane. That's when the frame rate drops from a constant 30 fps down to like 20-23 fps. Only when these addon contrails appear and only when I look straight down at the ground passing underneath my plane do I see the frame rates drop. It's definitely the contrails as there is not stuttering before the contrails appear or after I lower my altitude to make the contrails disappear. This is issue does not happen with the FSX vanilla contrails.

This is using Steve's latest Fixer version. As far as I can find, there is no option to turn on or off converting effects in the latest Fixer.

Anyone else having this peculiar issue? Thanks.