Deutsche Telekom AG's (ETR:DTE) T-Mobile USA is showing creeping signs that it's moving towards its possible new parent company, AT&T Inc. (T), in pricing and allowances.  While T-Mobile continues to offer competitive multi-line plans, some loyal fans have been fearful about a series of erosions to the company's "unlimited" data plans.

i. Bye Bye 200 MB "Unlimited", Hello, Overage!

In recent months "unlimited" was transitioned to a capped plan where T-Mobile did not charge for overages, but throttled data connections past your plans defined MB/GB limit.  Now T-Mobile may be preparing to make an even greater shift, with word leaking that there will be overages on new 200 MB plans, starting August 13.

The 200 MB plan is T-Mobile's most affordable tier, available for a mere $10 USD/month.  Existing customers can continue to use the plan in its current (overage-free) form, at least until their contract expires.

For new subscribers, you will get hit with $0.10 USD/MB fees.  That may seem rather high (AT&T's overage is $10 USD/GB -- or rough $0.01 USD/MB), but T-Mobile has softened the blow, capping the maximum overage at $30 or $35 USD, depending on what kind of line you have.  In other words, customers will likely reach the overage far faster, but won't risk the hundreds of dollars of overages that customers on some other carriers have experienced.

ii. AT&T to Grandfather T-Mobile Users

In related news, an AT&T spokesperson responded to our inquiry regarding how the possible acquisition will affect T-Mobile users' plans.  They stated, "T-Mobile consumers will be able to keep their rate plans for as long as they want to, even when upgrading to a comparable device, once the merger is completed."

We asked what exactly "comparable device" meant.  Our guess was it was based on the type of modem (3G, HSPA+), but it could also mean feature phones versus "smart phones".  The AT&T spokesperson was unsure of the definition and was unable to provide us with this information, so the precise details of the grandfathering scheme are a bit nebulous, even if it is clear there will be such a scheme.

AT&T has the second highest data prices in the industry, behind only Verizon Wireless (VZ).  Ironically their price follows their current size in terms of U.S. subscribers -- Verizon is no. 1 in the country, while AT&T is a close no. 2.  Despite the newly added limitations, T-Mobile's data plans are still cheaper and less restrictive than either of the top two.

Sprint Nextel Corp. (S) remains the only carrier to provide truly uncapped and unlimited smart phone data.  It also happens to be in a close competition with T-Mobile for lowest data rates.