There's good news and bad news on data caps for home Internet users.

Cox, the third largest US cable company, last week started charging overage fees to customers in four more states. Internet provider CenturyLink, on the other hand, recently ended an experiment with data caps and is giving bill credits to customers in the state of Washington who were charged overage fees during the yearlong trial.

Cox, which operates in 18 states with about six million residential and business customers, last week brought overage fees to Arizona, Louisiana, Nevada, and Oklahoma. Cox was already enforcing data caps and overage fees in Arkansas, Connecticut, Florida, Georgia, Idaho, Iowa, Kansas, Nebraska, and Ohio. California, Rhode Island, and Virginia technically have monthly caps but no enforcement of overage fees, according to Cox's list of data caps by location. Massachusetts and North Carolina seem to be exempt from the Cox data caps altogether.

Similar to Comcast, Cox lets capped customers use 1TB of data a month and charges $10 for each additional block of 50GB. Cox will introduce a pricier "unlimited" plan later this year, Multichannel News reported. If Cox continues to match Comcast's pricing, the unlimited data plan would cost an additional $50 a month above what customers normally pay.

Paying that fee for unlimited data would simply let Cox customers return to the situation they had before overage charges were implemented: paying a flat rate for Internet access, regardless of how much they use. But the same service will cost more.

Cox customers who subscribe to its gigabit fiber service get to use 2TB before paying overage fees.

Good news for CenturyLink customers

Data caps have generally headed in the wrong direction for consumers in the US home Internet market, and customers seldom have much choice in the matter because of a lack of competition. But the good news is that CenturyLink has apparently decided that the extra revenue to be made from overage fees isn't worth the increase in angry customers.

A year ago, CenturyLink started a data-cap trial in Yakima, Washington, imposing a 300GB-per-month cap and overage fees of $10 for each additional 50GB. But instead of expanding the overage fees to more cities, CenturyLink ended the "usage-based billing program."

"Because this approach no longer aligns with our goal to simplify offers and pricing for our customers, we have decided to end this program, effective May 3, 2017," CenturyLink said in an announcement that was detailed in a Stop the Cap article this week.

Best of all, CenturyLink will give bill credits to Yakima customers who were unfortunate enough to pay the overage fees.

"If you incurred overage charges related to this program, those charges will be credited and appear on your June or July monthly billing statement," CenturyLink said. "No action is required on your part, and there are no impacts to your existing CenturyLink service."

This is obviously good news for customers throughout CenturyLink's footprint, since it appears the company won't be expanding overage fees to new locations. CenturyLink has nearly six million Internet subscribers.

CenturyLink customers aren't totally in the clear, though. CenturyLink still has an "Excessive Use Policy" that limits customers to 150GB or 250GB a month and "reserves the right to disconnect your service after the third month of excessive usage in a rolling 12-month period." Customers exceeding the limit aren't automatically disconnected, and the ISP says it "encourages" customers to decrease their usage or upgrade to a higher speed before taking any drastic action. Back in 2013, DSLReports wrote about a CenturyLink customer who was kicked off the network for using too much data.

Cable providers like Cox have no trouble offering broadband speeds, but CenturyLink's Excessive Use Policy seems to be rooted at least partly in actual network limitations. CenturyLink offers fiber Internet with gigabit speeds in some areas and does not apply the Excessive Use Policy to gigabit customers. But much of its network is stuck on old DSL lines and sub-standard speeds. CenturyLink applies the lower 150GB data limit to customers on speed tiers of less than 1.5Mbps and says it takes "network health" and "congestion" into account when deciding whether to disconnect a customer who uses too much data.