Released: v14.4 of the Exchange 2010 Mailbox Server Role Requirements Calculator

Me in a Big Dilema... Please help.....I am doing a Exchange 2010 Transition for around 26,000 users and targeting to size for 40,000. In the current scenario we have 5 CCR and the storage of around 32 TB out of which only 15 TB is being utilized. When I used the Calculator to create 2 HA copies I was suggested a storage size of around 100 TB - 120 TB . Now the problem is I am having a hard time convincing my Boss  on the Storage required as he is asking me why has the storage grown 4 times. I have tried to convince him on the various types of profile and the calculations but to no luck. He is right in saying that if my current Infrastructure is under utilized why should I go ahead and invest more. I am worried as to what should I opt. Please help.