Why the slow pace of certifying NBU with Exchange 2013 CU's?

I'm not happy with the slow pace that Symantec takes to certify NBU with the latest Exchange 2013 cumulative updates.  Last time we had to wait 11 weeks.  Our inability to deploy CU7 means we are also delayed in applying an interim custom update Microsoft made for an Exchange public folder instability problem we're facing. 

Is there some kind of escalation we can do to increase the visibility of our dissatisfaction with the pace of certifying NBU with the latest Exchange CU's and versions?

Thanks,

Adam