It's actually standard UNIX quota soft/hard limits. So you have a soft limit of your (paid quota) that you can drift above for 7 days (that is the grace period

It's actually standard UNIX quota soft/hard limits. So you have a soft limit of your (paid quota) that you can drift above for 7 days (that is the grace period) and you have a hard limit of (quota * 1.1) that is ... a hard limit. We have an automated alerting system that emails primary and technical contacts in a progressively more aggressive fashion as you drift above the soft limit and approach the hard limit...