It looks like T-Mobile may soon take a page out of AT&T’s book when it comes to data plans. A leaked image shows plans to move their 200 MB/month data plan off of throttling. Instead, T-Mo customers will start being charged overage fees should they exceed that 200 MB limit. For now, it only applies to the smaller plan, but is troubling news none the less.

T-Mobile has been pushing its smartphones with claims of the best values, and no overages as of late, but apparently it isn’t working out as well as they planned. Citing the need to “remain competitive,” T-Mobile has decided to take away “unlimited” data, from those currently on the plan that grants 200 MB of data before throttling kicks in.

Those who come close to their limit will receive a warning (at 180 MB), and going over will incur an overage fee of $0.10/MB ($10/GB). These overages will only be possible up to $30 a month for Classic plan customers, and $35 a month for Value plan customers. We would imagine existing customers will be grandfathered in, as other carriers have done, but the wording seems vague enough that we’re reluctant to say so.

There are several interesting things to note here though. First, the new plan will not throttle you until you’ve used 5 GB of data (which is technically unreachable with the overage limitations of $30 and $35). This means that customers will be able to squeeze out an extra GB or so of unthrottled data with this plan, if speed is more important than quantity.

Once again, this only applies to the 200 MB plan. T-Mobile’s 2GB/unlimited oxymoron plan will still give you as much data as you want, with a speed drop after 2GB of usage. With AT&T’s pending purchase of the pink provider, T-Mobile’s long term future is anything but certain, in the mean-time make sure you check with T-Mobile to confirm whether or not you’ll be grandfathered in to avoid overages.

[via TmoNews]