Should N-S be in 3NT if not vulnerable?
I think that your adjustment to HCP is perfectly fine for your own purposes, but it's not within the technical definition of "high card points" (which solely include the 4/3/2/1 point count, or whatever other numbers you want to assign each honor) and exclude distribution points.  You're well within rights to consider distribution; but many automated programs will solely focus on HCP, including the link you sent, as far as I can tell - so when they say that two balanced hands with 25 points are optimally in 3NT, they mean the hand above to be in that collection.

I'd also say that those two hands look fine in 3NT.  They're both solid hands with dense honors yet still largely controlling the suits; little wasted value ("Jxxx" type stuff) and lots of T/9/8s also to round out the hands.  North can count 4 tricks in their hand even with basically nothing of value in South, and South similarly can count 3.5 tricks at least in theirs again with absolutely no help from North - 4 if you consider the diamond length to make the K fairly safe.  Each expecting the other to have 4 solo tricks plus one trick from fitting honors seems reasonable, don't you think?