If you open the machine control panel (gear icon on the right panel) while printing, it gives you a current percentage of completion. I don't know why they don't have an estimated time remaining since they give that time, but yeah.... kind of annoying.
I made a little webscript to do the calculation and countdown automagically. You can use it here if you want:
http://calibermengsk.com/3dprinting/timeRemaining.html
It doesn't update to the current real percentage obviously, so it can be off if for some reason your print runs faster or slower than expected, but you can just update the percentage at any point and hit the calculate button again.
It's all javascript and html, so it should work on any browser, including mobile.
Hope this helps
