I guess it all depends on your progression, so that’s why I asked. I only have the wisp avatar mission left on S3, so I work on that during VF, or when the daily PoV needs S3 maps like today. Chances are I will be completed that mission on next VF. As for S4, it is my lowest priority, so it won’t be for another week or so before I complete the latest maps in normal and hard.
But I was at a similar situation as you when S4 opened, so I did approach it similarly.