According to Handbook 44 and the laws that apply to a Class III L device, 200,000 lbs is the maximum gross capacity that any truck scale system can have and still maintain 20 lb increments in legal-for-trade-applications (10,000 divisions). For somebody to set up a truck scale with a capacity rating above 200,000 lbs, the minimum increment size jumps to 50 lbs and that is undesirable for obvious reasons.
There are scales with gross capacity ranges that go up to 270,000 pounds or more. Therefore, if you should happen to encounter a set of requirements or bid specifications that require a gross capacity of greater than 200,000 pounds (120 tons or 135 tons seem to appear now and then), that spec can be met, however, the system cannot be used above 200,000 pounds unless the end user is willing to operate with 50 pound increments.
On a related note, the GSE 60 series indicators have NTEP approved multi-ranging capability. For example, at time of calibration, the scale company can setup the indicator to read by 20 lb increments up to and below 200,000 lbs and then switch to 50 lb increments above 200,000 lbs.