The pics are much better now, thanks!
I'm at work, so I won't be able to import that .txt file to view it for about 6-7 hours, but someone else will probably get to it before me to make sure.
Can you put the 1812's in the same locations you had the PB2000's and run a sweep with no EQ? I would expect to see similar rolloff between the PB2000 and V1812, understanding that the tuning points are different, but the overall shape should be close. Your graph is concerning already though. It's starting to look like the PSA has a brickwall HPF at 23Hz. If so, that's super-lame.
It's helpful to have REW graphs at 5dB increments on the vertical; I've got to constantly adjust my graph scales when I do sweeps... it's just a lot easier to see what's going on with 5dB vertical. 10+dB on vertical makes things look a lot better than reality.
If there's nothing goofy going on with the biquads, then I'm thinking I'd recommend returning the 1812's. Keep about a grand of the return money in your pocket, and take 2 grand and change and try a VTF-15H Mk2 pair from HSU Research. I guarantee you'll have meaningful low bass. Heck, it's looking like you'd need over a dozen 1812's to match a single one of my TN1220HO subs at 16Hz, and it takes both TN1220HOs to equal my single VTF-15H Mk2 down low...
MiniDSP 2x4HD, UMIK-1, REW... The holy trinity for running multiple subs.