How much Target USL do you use on a cabinet run?

I am in the process of finishing the carcass parts for my kitchen cabinets. In all, I purchased 20 sheets of Birch ply. I'm two gallons into the second five gallon pail, and I'm wondering if I am on track.

The first coat has not gone on particularly well. I think that whoever made the birch ply (got it from a high end wholesale supplier) had serates in the sandpaper because every time I lay down a first coat of the Target USL, I get a ton of small bubbles, that look like small grains of sand. I sand that rough, and I mean rough initial coat (which I have to put down pretty heavy to get coverage on the wood), and then the second and third coats go on quite well.

I don't think it's an issue with my gun, because I can go from spraying a third coat that goes on quite well to a new piece of lumber that doesn't accept the USL well. I have used USL on cherry before, and the first coat is easy. I talked with Jeff Weiss at Target, and he said that the USL should go down well on Birch ply.

In any event, just eyeballing what I have left to do, I will probably be getting pretty close to finishing the second 5 gallon pail on the carcasses. This seems like a lot of finish to be using. I have dropped the pressure as far down as I can go (40 at the regulator and 20ish at the PSH1), and my overspray has not been that significant - compared to when I was pushing 60 at the regulator.

I wonder if my consumption of the USL is on track, or if I need to adjust something I am doing in the finishing process.

Thanks!

BTW, the burn in feature to the USL and the ability to level so well really take most of the "harm" to the appearance of the finish caused by all of the sanding and roughness.