Std faster than max. clutching or..??

I have a 2014 Outlander Max XT 1000. My buddy has a 2012 Outlander XT 1000 (shorty). Not that I normally ride this fast but we had to see…
My wot is 70-71 on flat hard pack. I have never hit my engine limiter.
His is 77-78 when he hits his engine limiter…every time.
Mine has 1200 miles on it now. His has 1800. Both machines are bone stock no accessories. My rear seat was not on the machine when we ran them. We ran them last summer and this year so far with the same results. Both belts should be in similar shape as we’ve ridden together since they were both new under same conditions and never in mud/water. Just trail riding & no pulling, plowing, climbing, etc. Nothing that would cause excessive wear to my belt.
We thought the difference was in clutching & that the max is clutched for carrying 2 people but after checking the parts lists for both machines, they are the same in Max and shorty from 2012 to ’14.
I would not think the small difference in weight would have that much of an affect.
I dont think there’s a problem with the machine, it’s just not as fast as I think it should be.
So what’s the deal? What do you guys think??