Thank you for the additional information.
Another question would be do you see any feathering to go along with the cupping? By this I mean thin flaps of rubber on either the leading or trailing edges of the rain groves in the tires? Beyond that, my best suggestion is to bump the tire pressure up to 40 psi in the front. I am basing this opinion on your description of the wear patterns being on both sides of the center of the tire, and it doesn't sound like it is in the center.
Unlike car shocks, that as they get old and tend to fade, can produce some unusual wear patterns, motorcycle forks are not susceptible to that. Keep in mind also that most cars get significantly more miles put on them than motorcycles, so they tend to see problems that we don't on motorcycles just because of the relative low mileage of the average bike vs the average car. If you have not changed your fork oil in awhile, it is a good idea to do that but more so to get the old dirty oil out that has abrasives in it from internal wear, which tends to accelerate wear even more.
I would also suggest checking the rim for trueness. Usually a rim that has a bend in it has other symptoms more obvious than tire wear, but in the interest of being thorough, it is worth a check. Also, along those same lines, I would suggest going through all the fasteners on the front suspension and torquing them to specs. Some of the fasteners are not torqued as tight as one might think. As you do this, you can check a couple of other things as well. First, I would suggest getting the weight off the front end, and loosen the triple clamp bolts on one fork leg, then attempt to spin the fork leg in the clamps. What you are looking for is a smooth rotational feel to spinning them. What you don't want is to feel a tight spot then a loose spot. That would be an indicator that a fork leg is bent and requires straightening or replacing, depending on the severity of the bend. After you check both fork legs for being straight, tighten the top triple clamp bolts, leave the lower clamp bolts loose, and loose the clamp bolts on the bottom of the right fork leg that clamps on the axle. With those fasteners loose, you will get on the bike, hold the front brake tight, and bounce on the front suspension several times. What you are doing here is ensuring the forks are not "pinched" by the axle clamp. You want them to be straight and allowed to find their natural center so there is not a binding action in their movement because they are not parallel. Once you have bounced several times on them with those clamps loose, go through and torque everything to the factory specs. Everything from the axle, clamps, front fender, upper and lower triple clamps, everything.
Lastly make sure your fork rebound isn't set too slow. Typically manufacturer's have the stock setting fairly close to the middle of the adjustment range.
Interestingly enough, Michelin does not recommend the use of dry or liquid balancers/sealers or any other balancing materials. Tires and Tubes into which these have been injected will not be covered under warranty.
You never mentioned who was mounting the tires and what method they were using for balancing. As ironic or inconceivable as it sounds, Michelin recommends hanging the tire from an axle supported by low drag precision bearings and spinning it by hand and seeing where the light spots are. They do not use computer spin balancers. Strange but true. Even on road race bikes that routinely go 180+mph, they balance them like that.
As far as the brands of tires go, I don't put much stock in anything a Shinko tire does. Shinkos have 2 purposes in this world as far as I am concerned. 1st, to keep the rim off the asphalt, and 2nd, be a low cost alternative to good tires. The only point of note that I took away from that was the Shinkos lasted longer than the Michelin's. My best explanation for that would be the Shinkos have a lot harder rubber compound that is more resistant to wear. Although it may last longer, hard rubber does not have the grip softer rubber has. That is always a trade off in tires, you can get tires that last a long time, or grip like crazy, but you can't get both in one tire. (they are trying to get closer to that with some of the sport bike dual compound tires)
If you need any of the specs I mentioned, let me know and I can provide those for you.