The sustained top speed is 10 mph faster on the 2016 because of the IPM motor. Just curious though, where do you live? Texas? I know they have an 85 mph speed limit there. But I wouldn't expect more than about 60 miles range at those speeds. Or 75 miles with the powertank and that's if you're in a race type tuck.
How far is your commute? If less than 30 miles each way, you should be fine. Or if you can find a place to plug in at work than don't even worry about it. At about 80-85 mph I get about 80 miles range and it will hold highway speeds of 70 mph on my bike all the way down to 0%. Then it starts to slow down gradually while I can go another 5 miles with the throttle twisted all the way, 10 miles if I slow down and milk it. I have a 2015, the 2016's should be even better.
Zero's speedometer is pretty accurate within about a mile per hour. Many gas bikes I've had like my R1 the speedometer read 5-8 mph fast. So when it said I was doing 100 mph I was really doing 92-95. Do you ride your gas bike at 95 mph indicated? What kind of bike is it? Only reason I say this is you might really only be going 90 mph. But the 2016 Zero SR should hold 95 mph for your entire commute. Go take one for a test ride and tell us what you think!!!
My commute is 13 miles each way so I'm not really worried about the range. I live in California.
During the test drive I was only able to touch 90 mph at about 98% SoC, so it didn't really help me understand what happens as charge drops during sustained speeds. My current bike is a kawi concours with a 1400cc engine and I may (or may not) routinely cruise at 100mph+ speeds as the road conditions and traffic allow it.

Because of the test drive I really want to get one. I was amazed at the acceleration and feel of the bike in general. Again, I REALLY want to get one, but one of the things I want to know is if I'll be able to cruise at 90mph for extended periods of time. I know that over 100mph is really not possible though and that's of real concern to me, as silly as it might sound.