Once the mfg's saw that ATF would wreck the p/s system then the "Power Steering Fluid" products started showing up on the shelves at the dealers as well as the parts stores.
Thanks for that info Larry.
My E30 BMW has a rack leak (like most of them) I used a really cheap stop leak and it worked well for about 8,000miles before a leak showed up again. I then used a more expensive additive that did nothing at all.
However, if I had been using power steering fluid instead of ATF, perhaps I would have had better results.