June 1 change accompanied by a higher cap, higher price for unlimited data.
Starting June 1, Comcast customers who face data caps will not be able to rack up more than $200 worth of overage charges in a month.

Comcast will continue to charge an extra $10 for each 50GB allotted to customers beyond the standard data plan. But prior to this change, there was apparently no limit on how many times per month a customer could be charged the extra $10.

Comcast confirmed the change in one of its data cap FAQs. On a DSLReports forum, a customer in Georgia posted a copy of a letter in which Comcast describes the change.

As previously reported, Comcast is also raising the monthly cap from 300GB to 1TB beginning June 1. To accumulate $200 in overage charges, customers would have to use an additional terabyte.

Comcast will also let customers purchase unlimited data for an extra $50 a month starting June 1, up from the current $30 or $35. When Comcast introduced the unlimited data option last year, it was only available in some cities and towns. But with the June 1 change, it appears every customer in one of the data cap trial markets will be able to buy unlimited data. Customers who are signed up for unlimited data will pay the extra $50 each month even if they don't go over the cap. According to the letter posted on DSLReports, customers already paying for unlimited data will keep their current pricing until the end of 2016; after that, they will pay $50.

Comcast announced its data cap trials in 2012, testing out different packages in different cities in preparation for a possible nationwide rollout. With the latest changes, the data caps have become more uniform across the trial markets. (Before 2012, there was a 250GB nationwide cap, but it was a hard limit instead of one that could be exceeded as long as customers paid overage fees.)

Comcast says it made the most recent changes because it has "listened to customer feedback about wanting a carefree online experience that doesn't require them to think about their data usage plan." But based on complaints filed to the Federal Communications Commission, it seems many customers would prefer no caps at all.

While Comcast offers Internet service in 39 states and Washington, DC, the data caps are currently implemented in the following areas: Huntsville, Mobile, and Tuscaloosa, Alabama; Tucson, Arizona; Little Rock, Arkansas; Fort Lauderdale, the Keys, and Miami, Florida; Atlanta, Augusta, and Savannah, Georgia; Central Kentucky; Houma, LaPlace, and Shreveport, Louisiana; Maine; Jackson and Tupelo, Mississippi; Chattanooga, Greeneville, Johnson City/Gray, Knoxville, Memphis, and Nashville, Tennessee; Charleston, South Carolina; and Galax, Virginia.

When Comcast announced the data cap trials in 2012, the company claimed that the purpose and "sole goal" of its data caps were "simply to ensure that all of our customers were treated fairly and had a consistent and superior experience while using our high-speed data service." But more recently, a Comcast engineering executive acknowledged that the cap is a "business policy" and not a technical necessity.