Can you adjust the feet underneath the stove unit?

Check the height of the cabinets underneath the stone. My bet is that is where the issue arises. Not always, but usually. Raising the legs on the stove is the obvious solution if it is the cabinets and you don't want to pull everything to reset them.

Is the low piece of granite relatively small? If so, you can fairly easily pull it off and shim the granite up to the level of the other piece and then raise the stove.

Its slightly more difficult to go the other way by shaving down the cabinet top with a plane or sander.

If you post the layout of the counters or a picture of the whole situation it would be easier to give advice.

Oleksandr Havrylyuk:

Your stone thickness is probably well within industry standards for thickness variation. Calipers aren't used; maybe eye up a tape measure.

Pull the stove. Set a 4' level across the opening in an "X" fashion. If the tops are level to each other, adjust your appliance feet. If not, you may be able to shim the tops a bit.

I found that one of my quartz counters was not level after the fabricator left. The counter on the left of the range sat higher in the front, than the back. (The range needed to be raised after the quartz was in, so it was quite a noticeable difference, in my view). I had him come back and he said it wasn't his job to make the counters level. (Which sort of blew my mind.) He had replaced laminate counters, which are wood underneath of course, and they were perfectly level - both flat even with the range. He also stated that the difference was within tolerance. I didn't agree, and I threw a bit of a fit. He said the only option was to remove the counter, and then I could hire someone to level the cabinets underneath, and he would come back and reinstall. Short of that, he could try shimming along the back with very slim shims. So we tried that, which raised the back a little and lowered the front. Then we raised the range to the proper height, and that was enough to live with. So far, so good.

I had to paint and caulk under all the new counters anyway, regardless of this one counter. I assume that is normal, after replacing laminate - which has a dropped lip.

". I had him come back and he said it wasn't his job to make the counters level. (Which sort of blew my mind.)"

Be sure to put that in the review for him. Thats BS.

It really isn't the counter installers job to level the cabinets. Counters are installed onto level cabinets.

barnaclebob, yeah I thought that was sort of wacko.

ksc36 - they should be. All I know is that my laminate counters were level. If there was a notched area in the underside of the laminate to make it level, I couldn't tell you. I think it's poor workmanship to not check the level before laying the counter. It might not be the fabricator's job to level them, but it damn sure should be their job to let me know that they are not level before putting the counter on.

"Shims are commonly employed to level the stone countertops. Shim material may be wood or plastic. Maximum spacing between shims is 2'- 0" (600 mm). Alternatively, longer spacing between shims may be used if the stone is supported with a noncompressible filler material (usually epoxy or polyester resin). This practice is often referred to as “hard packing.”

http://www.marble-institute.com/default/assets/File/consumers/homeownersconsumer_countertop.pdf

"Some pros here were saying that granite must lay flat otherwise it may crack" that actually exactly the opposite of what's correct. Given imperfect cabinets and the backside of slabs which is usually not flat shims are a necessary part of a granite or quartz countertop install. Whoever those "pros" were didn't know what they were talking about. Cracks come when countertops are improperly or inadequately shimmed.

If you want to end with the laser, you have to start with the laser

Chess:

I've had disagreements with the MIA previously, and they're wrong about wood shims too. Wood shims aren't dimensionally stable enough for stone installation, they dry up and shrink too often. Modern composite shims or solid plastic shims are preferable.

We don't have this problem in America because our clients can't read the tape measure, thank god.

"I shoot the laser across the front. On the left the laser shoots right at the top edge of granite. On the right it shoots below the top edge as you can see on the picture. The laser is level."

You're only getting a level check across the front edge with the laser. You must check the plane of the slabs to each other on each side, side to side/front, side to side/rear, rear left to front right, rear right to front left, and front to back each side. This is why you put a 4' level across the appliance opening in an "X' fashion as mentioned earlier.

Joseph Corlett, LLC, about the shims, that certainly makes sense. Wish my fabricator had thought about that before he used wood shims on my counter. But hopefully it will be fine,

Ryan Olivieri, Inc.

"We don't have this problem in America because our clients can't read the tape measure, thank god."

Ummm...maybe not where YOU live.

Chess, thank you for the document. Looks like my granite slabs are within the specs. We are talking about 1 mm adjustment on the back and up to 1.4 or so on front. I don't know if I should bother... I was concerned mostly about backsplash installation issues because of the unleveled countertops.
If I go with shims, what do you, guys, recommend for filling the crack? I don't have an overhang like I had with laminate countertops to hide them.

"If I go with shims, what do you, guys, recommend for filling the crack?"

Color matched paintable caulk.

Like suggested above....paintable caulk. My cabs are white so that was an easy choice.