jabres... Your question intrigued me as well. People often look to 3/4 models for higher payload and tow ratings. Granted this is an SUV not a pickup but 7600 does sounds almost unbelievably low. I talked to a GM friend of mine briefly and he directed me here...
2005 Suburban 2500 LS 2WD--tow rating - Chevrolet Forum - Chevy Enthusiasts Forums
Even the Chevy fans agree with your numbers. I'd say the reason for the 100# difference between your numbers and theirs is likely 2WD vs. 4WD. I don't know this to be a fact, just an educated guess. It's on the internet so it has to be true!
Bottom line and the reason for my post was this. NEVER and I mean NEVER talk to a dealership regarding towing capacities. In the past 8 years I've talked to 6 car dealerships and 3 RV dealerships about ratings. Only one ( a small RV dealership that specialized in popups and ultralite's was honest. The rest gave outrageously inflated numbers. I went with my dad 8 years ago when he brought his RAM. They tried to convince us that a 1/2-ton 4.7L w/ 3.55s could pull something like 9,200lbs! When I bought my pickup I all but punched the Chevy salesman. He kept saying "It's a Silvarado, it's pull anything." Their own books showed the towing capacity at somewhere around 4500lbs. And I had to show him that. (Before anyone asks, this was 2010 and Chevy was in the midst of their "best in class fuel economy gimik. This truck had the lowest gear ratio I've ever seen. Could be wrong but I think it was less than 3.31.) Anyway I've gotten a little carried away here, don't be afraid to pass up a "good deal" if it doesn't suit your needs. There will be other rigs
That said according to what you've provided it sounds like your good as long as you keep the weight of passengers and cargo in the truck under 1000lbs. That said I haven't checked your GVWR either so you'll want to double check that first. The only thing is this really doesn't leave you a lot of wiggle room for future endeavors.