Comcast is pushing new technology it says could change the way you watch TV and the way advertisers buy time on it.

Right now, ad buyers pay for C+3 ratings – those that measure the number of people who watch their ads in the three days after a TV show airs. For a show like NBC’s “The Blacklist,” which airs Monday nights at 10, that means they pay for people who watch live, plus On Demand or on DVR until Thursday night.

Also read: Network Execs Explain Which Ratings Matter — And Which Don’t

But Comcast has another idea to reflect the reality of how many people watch older episodes. It has found a way to insert the same new ads that appear in every new episode of a show into all previous episodes of the show as well, over the same three-day period that C+3 measures.

That means you would see the same ads whether you were watching a brand-new “Blacklist,” or catching up on a previous episode. Comcast recently completed successful testing with NBC — which it owns — and ABC. It worked with Nielsen to measure viewership.

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Comcast believes that if viewers had more incentive to watch older shows, networks could start making whole seasons available on demand. They might then be able to charge advertisers more to buy time.

It’s a new twist on the already new technology of digital ad-insertion, which allows advertisers to add fresh ads to older shows. The latest technology, called On Demand Commercial Ratings, could sync up advertising precisely across a whole season of television. New ads would be inserted across the whole season as each new episode aired.

Comcast, the largest cable provider, says 40 percent of shows are viewed in the C+3 window, and 60 percent beyond it. And networks usually make only a few older episodes available on demand. The new system would let viewers binge watch a whole season, and let networks charge advertisers to run the latest ads.

“We can actually deliver higher ratings and higher commercial ratings,” said Rob Holmes, Comcast Cable’s vice president of advanced advertising.

One network insider recently told TheWrap that networks would eventually like advertisers to buy ads based on a C+7 rate, the number of people who watch a given show’s commercials over a week. That will be an easier sell when networks can offer advertisers more options, and promise greater control over what ads viewers see.

But before you start seeing more episodes available — with the latest ads — Comcast will have to get networks on board. Besides ABC and NBC, TNT has also expressed interest.

But the biggest step is persuading advertisers to pay enough for ads to make the new technology worthwhile for networks.