Yes, this is correct. In order to make the election to stop contributing to CPP, you must be between the ages of 65 and 70 and receiving your CPP Retirement Benefits.
This term is found on the Schedule 8 itself from CRA regarding the date you can make the election: "The date cannot be earlier than the
month you turn 65 and you are receiving a CPP or QPP retirement pension".
https://www.canada.ca/content/dam/cra-arc/formspubs/pbg/5000-s8/5000-s8-18e.pdf
