When is a stream not a stream? Billboard, which publishes the definitive album and song charts for the U.S. music industry, has had to ask itself that odd question in the last few months. After facing pressure and criticism from subscription music-streaming services, the trade publication announced last October that it would revamp its chart formulas, which it populates with data from stats firm Nielsen, to give paid streaming more weight than free streaming.

Those new formulas are here. Billboard announced this week that beginning June 29th, the Billboard Hot 100 (which tracks songs via sales, radio play and streaming) will take on the following point system for streaming:

one full point per play for paid subscription streams

two-thirds of a point per play for ad-supported streams

one-half of a point per play for programmed streams

And the Billboard 200, which tracks albums, will have two tiers:

paid subscription audio streams (equating 1,250 streams to one album unit)

ad-supported audio streams (equating 3,750 streams to one album unit)

Previously, paid and ad-supported (or “free”) streams had entirely equal weight in both charts. Under the new rules, paid streams carry substantially more value than other kinds. So a song that gets played 100 times on a subscription service will collect 100 points, for instance, but will only snag 66 points if played on a free service. Free plays are even further penalized on the albums chart, where it will take three times as many free plays of one track to equate to one paid play.

In 2019, things will get even more specific: The Billboard 200 will “further separate paid subscription audio streams into two distinctive tiers, with the higher tier including paid subscriptions that provide full music library access and no restrictions on on-demand functionality and a secondary tier that reflects paid subscriptions that provide a partial music library and/or limited on-demand functionality.”

What does that all mean? Streaming, the biggest form of music consumption these days, was already the most dominant factor in Billboard’s charts – so the changes are expected to have significant impact, especially in the albums chart where a stream on a paid service like Apple Music will count for three times as much as a stream on Spotify’s free tier.

Because the new rules disfavor ad-supported services, they might upend certain artists or genres that pull in most of their listens from YouTube. But putting together all these methods of listening into one system remains a tricky matter, and the charts still have their share of critics. “Billboard could have a free chart if they want, but the chart that people argue for, that they strive to be Number One on, has to be a real chart,” Apple Music head Jimmy Iovine told Rolling Stone in December. “Otherwise, they’re mixing – no pun intended – apples and oranges.”