They had to come up with some name for the third set of tasks,however, I came to the conclusion a long time ago that, the title Premium was an accidental or deliberate misnomer.
I haven't paid much specific attention to the tasks recently, but had assumed they were still all pretty much the same, and for me not very fruitful, probably is some, as always mysterious formula,and connected to progress.
Now, after reading Laird Brinni 's post , who I had wondered if was still playing,I had a relook at the tasks.
After a small sample, I came to much the same conclusion as before, poor stuff and not many gems, the only difference seems to be that gems now only fall in PREMIUM, and no where else.
So either my memory is playing tricks with me, or sometime in the past, either I never saw a notice to that effect,or they did one of their we changed something, but we aren't telling you that we did routines.