Change when Quota almost reached warnings are received

Hello,

Right now we, and our customers, receive a warning about the quota being almost reached when the backup quota reaches 10% of the full size. 

Example: When the quota is 100GB, after reaching 90GB the warnings are sent.

Another example; When the quota is 500GB, after reachting 450GB the warnings are sent.

Is there some way we can change this settings so the warnings are sent perhaps at 5% or lower?

Hope to hear from you soon