Thanks Elvis. This section:
"Each token issued by StandardID server has an expiration time. If the token expires then flex.bi will request a new one using the supplied refresh token."
I believe the access token has an expiry of 1 hour. If the refresh token has an expiry of 15 minutes, how can it be used to get a new access token? Otherwise, flex.bi would lose authorisation unless it refreshed data more than once an hour. Or am I misunderstanding things?