Absolutely. I had discovered this a few weeks ago, it actually works, and I was able to delete those stupid duplicates - I had routines like “between sunset and sunrise, if outside temperature drops below 14C, close all blinds” and then, because that wouldn’t work on a cold day when temperature was already below 14C at sunset, “at sunset, if outside temperature is below 14C, close all blinds”.
With that new switch, I kept the former, enabled “execute at start time”, and deleted the latter.
Philips Hue still has excellent changelogs, as does Apple for most of their official apps. Although come to think of it, they are usually called “release notes” now, I guess.
Yes, I created a Rule and read the JSON straight away to see what approach they used. So when I suggested it was basically the same as adding a second routine I did mean it literally.