Earlier quoted context omitted.
I've never seen anyone propose moving in the opposite direction of summer time before. That seems needlessly awkward to me.
I don't think it is proposing that. From what I can tell their proposal is a (somewhat awkward) way of saying some countries will stick to their current summer (standard) time next time they switch to it. Other countries will stick with their current winter (DST) time when they next switch to it.
But yeah, assuming they want to do the magic in September: It would mean for countries where UTC+01:00 (standard time, winter time) makes more sense, they'd move to UTC+01:00 when the next switchover date in September shows up, whereas for countries where UTC+02:00 (daylight savings/summer time) makes more sense, they'd stay on that TZ past the September switchover date. They'd have to assign new names though, one can't have 1 timezone with 2 different names...