didn't make a claim, just pointed out all the possibilities. The PSU is the power brick? (not up on these acronyms)
So they just changed voltages and put your old power bricks in the new bases? Sounds reasonable. Chargers matching devices has long been an annoyance with suppliers of consumer devices.
They could have changed voltages just because of a bargain on supply of that particular brick.
They could also have found the original voltage was not optimally designed. Tweaks. Who knows?
Unfortunately a specific voltage power brick (switching power supply) might only be made for this company's application and be sold only with the entire base -- including the old ones.iRobot
parts tend to be in greater supply because millions of units were sold over ten years. Neato's still new.