BonusEmails has 1000 referral levels. It is like this:
Levels 1-2=10%
Levels 3-5=5%
Levels 6-10=1%
Levels 11-1000=.01%
Perhaps what you have experienced is the common CAC problem of someone in your downline unsubscribing and making you lose referrals?
I recently lost something like levels 14-35 in my downline, I guess because someone unsubscribed, but since each person in those levels was only earning me .01%, I will not lose any sleep over it.