Their announcement made it sound like the rates were approved because they were approved by the Board of Governors, but the proposal is also subject to approval by the Postal Regulatory Commission. The Commission can accept, reject, or (I believe) modify the request

An extra ounce would be reduced to 15 cents, making a 2-ounce letter 70 cents total. I could not find the proposed rates for packages in the longer formal notice of the proposed rates.

Here's the confusing announcement that makes it sound like a done deal, even though it isn't yet:
http://about.usps.com/news/national-releases/2018/pr18_086.htm

Here's the formal legal announcement, which has a lot of gobbledy-gook:
https://www.prc.gov/docs/106/106732/Notice%20and%20Attach%20ACD.pdf