Keith's note: Too bad this reporter (or his editor) did not really understand what NASA was telling him. This article title is simply wrong. This has nothing to do with a disagreement. Rather it has to do with an agreement made in the 1990s allowing the Russians to use their heritage hardware and the U.S. using its existing systems, and then looking for ways that each approach can complement, supplement, or improve upon the other's systems. If nothing else having more than one approach to things offers dissimilar redundancy - something that has saved the ISS program's butt more times than many people know. In the mean time and engineering and operational synergy has emerged from the ISS program with unexpected wisdom that can be applied to future missions.
Oddly, despite this totally inaccurate title, the author even notes the concept of dissimilar redundancy in his article: "NASA has decided to switch to silver-ionized water on future missions, but Carter says he likes that there's both silver- and iodine-treated water aboard the ISS: "It really makes a lot of sense," he says, "to have dissimilar redundancies in the space station in case one of the systems has problems."