Mark,
I don't know how long you've been in business or how many decks you've done but I wish you the best of luck with Penefin. We have used it in the past in your area and other areas on the west side (at owners request) and had nothing but problems with it. We have had decks turn black within weeks of applying this product.
I am assuming that you are a req. contractor as the state requires. This product will give you a lot of problems with the contractors board and will cost you a lot of money down the road. Don't expect any back up or help from the manufacture, been there, done that. They really like you when you are using their product but when you have a problem, you didn't apply it right. They will tell you that you have a mildew problem but their product doesn't mildew. Still trying to figure that one out.
Our climate, along with Western Washington is about the worst there is for finishes. We have tested many, many finishes and found that they can't hold up under our climatic contitions. Yes, we even tested Ready Seal, lasted for about 3 months before turning black.
In choosing a finish for your area (Oregon), keep in mind that it has to last at least a year (soon to be two years) or you may be redoing them at your own expense. The contractors board shows no pitty to the contractors.
If your interested in a good finish for your area, let me know.
Jim Bilyeu
Exterior Woodcare