Data throttling is the new norm for wireless carriers. If you’re in the top five percent of data consumers on AT&T unlimited data plan, for example, you might find your connection speeds severely slowed after you reached a certain limit. According to a recent study by wireless bill analytics firm, Validas, the bar that’s being set for that limit doesn’t have a set place.

The New York Times reports:

For Verizon bills, the top 5 percent of data customers on unlimited plans  used nearly the same amount of data as those on tiered plans. And for AT&T, the top 5 percent of customers on unlimited data plans used only slightly more data than those on limited plans.

What’s seems to be happening is that, if you have an unlimited plan and you reach data amounts equal to that of limited plans, your carrier starts to apply the throttle. And then there’s this riddle of the Sphinx, as the Times again reports:

Validas raises the question of whether the carriers were throttling simply because they want unlimited data customers to switch to limited, tiered plans. It is a befuddling question because it could potentially cost customers more over time. After all, how can a network be out of capacity if it can serve a customer on a limited plan without throttling if the heaviest data users on both limited and unlimited plans are consuming roughly the same amount of data?

Expect this topic to bubble to the surface as the Mobile World Congress conference gets underway in Barcelona next week.