That number seems awfully low to me, and I also honestly don't think that if there's a marked weight limit for these things that any customer of Doppelmayr would be routinely overloading cabins with more weight than what is listed - among other things, that would likely leave them open to massive lawsuits if something were ever to happen. I could maybe see a 705 kg limit for a 4 person lift, any chance it was that instead?
The only information I could find kinda implied that for what I think these gondolas are (without having read enough through to know the exact model) would be something like around an 1800kg carrier weight including payload - so the whole thing including people would be max 1800kg. No idea what the weight of the gondola itself actually is, but it wouldn't really surprise me if it comes in a lot lower than most people would expect. 1800kg is around 4000 pounds, and I wouldn't be surprised if the gondola itself is under 1000 pounds, which would leave around 3000 pounds for people weight.