Permethrin and Pertex

From Sawyer's (they make a popular permethrin spray) website:

"−Will Permethrin ruin my clothes or equipment?

No. Permethrin will not damage clothes or equipment. Unlike DEET, which may harm some fabrics and materials, Permethrin is compatible for use even on fragile fabrics such as silk, plus all synthetics and waterproof membrane fabrics. Permethrin will not affect plastics or finishes. IF IN DOUBT, try a sample on an obscure surface area, especially on delicates and check it after 24 hours of exposure.

Sawyer® Permethrin Insect Repellent is odorless, non-greasy and non-staining after it dries. Permethrin can be harmful to aquatic creatures such as fish, so do not spray Permethrin around fish aquariums."

I've saturated a wide variety of technical fabrics with it without any discernable issue, but not Pertex specifically. IIRC pertex is made from 'regular' fabrics anyhow.

Why would you want to treat a down jacket? I've seen some big skeeters in my day, but none with a proboscis that long.

Also recommended for tents and backpacks, according to the label… ticks can latch onto other gear and still reach their "promised land". :^)

This prompted me to read the label more carefully. I thought the treatment was good for six washings. Actually, it's good "for six washings OR 42 days", after which re-treatment is necessary.