You must be using a pretty strongly lofted 6i to be hitting it that far at only 84mph. I can carry a 7i about 180 pretty easily and I use the soft stepped X in C tapers, but I definitely have about 8-10mph of clubhead speed on you. I love them for the feel and dispersion, and I happen to fit them pretty well for trajectory, but they ain't cheap. I went with soft stepped X simply because I wanted 130g instead of 120 or 125. I was recommended to get the S+.
The reason you hit it so far is you create such high launch and low spin. It's great with the driver and fairway woods, but it results in a knuckleball that rolls 20 yards. You also manage to generate a pretty high ball speed relative to your swing speed, so I suspect some combination of very hot irons and a distance ball.
The max height is interesting, because most tour players shoot for a 90 foot/30y max height on every club. Your max height is about perfect, however most pros have a descent angle of at least high 40s in their irons, over 50 in short irons. That's because they're putting on a lot more spin on a lower launching shot so it will come down steep, peak late, use up its energy sooner, and take less of a bounce. The actual spin on the ball doesn't do much until it's already settled on the green, so spin-checking is a bit of a misnomer. If you can get a 30+ max height and 48+ on descent angle, odds are you'll stop the ball with your irons, regardless of your actual spin number.
As for your dispersion and consistency, both are really good to be honest. http://www.pgatour.com/r/stats/info/?337 The pros average, from 175-200 yards, anywhere from 30 feet for the best in the category to about 40 feet for the worst. That's 10-13 yards offline, assuming good distance control. Given that you aren't playing on tour greens, but that's still pretty straight hitting by the looks of it.
I'd recommend against using the C tapers in this flex, though you might be able to play like R+ or R (Jim Furyk plays R+ and his dispersion is pretty good, his SS is even higher than yours by a bit). I'd possibly look into the head or loft, and most likely consider a switch to a tour or higher spin ball just to get the spin numbers up and the launch down slightly. But unless you're playing really low spin equipment already, it's your technique that's causing a really low spin and high launch for irons, even with a tight dispersion.