I haven't yet seen on this board anyone updating with 2 PCs across a P2P. I have one running ASN (and other flight planning stuff) and the other FSX:SE. I use Saitek X52 controllers so I'm not updating my FSX:SE machine yet until the drivers are out of beta, but I'm in the middle (as I type) of upgrading my secondary PC running ASN to Win 10.

I should (hopefully, fingers crossed) end up with a hybrid P2P with one on Win10 (32 bit ?) and the other on Win 7 (64bit). One of my reasons for doing this is that we're all going to have to move to Win 10, whether we like it of not (eventually), so the sooner I can get some experience with it the better. I've had to deal with the consequences of the strategy "if it ain't broke don't fix it" in my day job, and it is a false and dangerous way to operate computer systems.

I'll let you all know how it goes. 

So far so good. The first flight came up with an ASN error that it couldn't write to the FSX folder, but then I had to stop and do other stuff for the wife. When I next fired up my PCs I refreshed the Homegroup (P2P state) and gave it RW access to the top folder in common\FSX. I've just finished a flight around the block at EGKA where ASN updated the weather a couple of times, and this time there were no errors.
I was reasonably impressed with the Win10 install that it found the P2P network and configured itself to maintain it. So apart from this minor hiccup with ASN fingers crossed there's no more gremlins to find.