My experience is different than what you are saying here. I have rented ASVs, in the past, and have had derailment issues. I demoed a Cat 257 (has the ASV undercarriage) for about 40 hours. The machine was used for dirt grading, pipeline bedding (with sand), and spreading/grading road base. When I decided I did not want to buy the machine they took it back. A week later the dealer called and said that I owed them $5,600. One of the front idlers (plastic) had a hole in it. According to them both tracks were ruined so they wanted me to buy those too. I don't abuse machines. I have high hour machines (even VERY high hour) as evidence. I used this machine in the manner I would have any other. This undercarriage has serious limitations (just look in the manual) that would be a deal killer if I was looking for a tracked machine. Restrictions like no driving across slopes, or no turning on grade transitions. This would be a great machine for mowing lawns I guess but I digress. How can $5,600 in 40 hours be concidered anything but VERY high maintenance costs? BTW that money is exclusively an undercarriage cost. That's $140 per hour plus purchase price, normal PM costs of the machine, operator, overhead, and, if you dare, profit. It's unfortunate. I really liked the way the machine worked. It had a very smooth ride especially when you consider that it's a tracked unit.
That sounds to me like your CAT dealer was trying to put the screws to you and needs to have their head examined. I've always contended that CAT had no business puting a 257 on that undercarriage anyway because it'sa ton heavier than ASVs machines. I have the same undercarriage on my RC50 and I couldn't dream of incurring that much cost in that short of time and I've done a lot of the same types of work you have done. I have well over 2,000 hours on the machine and I know it hasn't cost me that much, and I've puchased new tracks and a few rollers. Typical CAT.
As far as not being able to operate on a slope...my machine has a slope indicator that came standard on the gauge console and the ASV manual even rates it for slope work. It must just be a CAT thing.