Light flow works just fine for me? I mean, I don't think there's anything such as a global switch but just setting the color to white for all apps should do.
I bought the PowerCore+ 20100 mAh about half a year ago and it works great except for the cable which is a surprisingly poor quality, so I also bought this universal cable and I'm pretty much all set with all my devices while travelling.
I went gradually down from the solid 4.5 hours of SOT when I bought it to the current 3.9 or so. Not terrible esp. considering the fast charge but I do have to recharge during the day and that's enough to make me unhappy.