FDA Requirements on Fill Levels

Hi Everyone,

I am currently looking through FDA's site to see if i can find any regulation or guidance document determining the fill level of a package.

We have always set our company standard at 70% or more of the package.  We are being asked to proove that we cannot go below that for a private label party that wants to have a 30% fill level. 

I was hoping someone might be able to help direct me more quickly.

Thanks in advance!