I got a call from Tire Rack on Monday saying that they show the 255/40-18 as a rear fitment size. They said nothing at all about load rating and such.
The load rating difference from 98 to 95 is 132lbs/tire, or the equivalent of 3 more adults which I very very rarely (like 2 times a year) have that much more weight in my car.
I'm not sure how the tire is manufactured differently to accommodate the extra weight. If it is softer side walls then maybe these 95Y tires will have a more comfortable ride. On the other hand I may get a bent rim from a pothole, though Texas roads are immaculate compared to where I'm from in Michigan.
Anyway, it's a risk I'm willing to take factoring how/where I drive.