Login by cookie and Rate Limit

In my system authentication is in radius, and hotspot users have Rate Limits enforced by ‘Mikrotik-Rate-Limit’ Attribute in radreply table. What happens if a user is logged in by cookie, does it get the rate limit set by radius at its last login by radius authentication?

As far as i can see there no field in cookie that tells about rate limt, am i wrong?

A hotspot user may buy higher rate limits for a while and after that period its rate limit should be back to a lower default value or if no default for its group then it should expire; I check expired users in database periodicaly and delete cookies for expired users, but how can i know a cookie rate limit is different than the one in database and delete it?

Rate limits can be found in queue/simple objects, but to check all hotspot users rate limits by comparing database and queue/simple object values is not the best way for performance reasons.