The Zing price went up since Vials introduction but it seems like it's slooowly going down, we'll see how will that unfold.
All the ROI calculations are solid but only if Zing token price stays constant. The only way to increase the price is to have much more updates and to have more burning.
Yeah you are right. The APRs and values all depends on the price of ZING, that can fluctuate depending on the changes in the drips.