exchangeRefreshTokenForAuthTokens not returning new refresh_token as stated in documentation

I'm trying to get a new refresh token without having to use my npsso token. I was hoping that `exchangeRefreshTokenForAuthTokens` would do this as the description of this function in the documentation makes me think it should.
> This function lets you exchange your refresh token retrieved from your initial log in for a set of new access and refresh tokens. By using this function, you no longer need to constantly retrieve a new NPSSO.

Unfortunately, it returns the refresh token I use to make the call, and the "refresh_token_expires_in" property doesn't reset so it keeps counting down. Can I only get a new refresh_token once the current one has expired, or is this function broken?

I'm looking for something that returns a new refresh token without the need of my npsso. Basically I want to keep my authentication valid as long as possible instead of having to login to playstation.com every 2 months.