You forgot the major expenses ,
1. Hard disks, With every TB of increment in shared data, we will have to add that much of disk capacity in every city
2. Internet connection cost, with every single Mbps of increment in data upload rate, we will have to increase the capacity of every cloning link.
But yes , the tariff proposed by our host suits our needs.
OH! i thought your server and storage expenses are covered in the starting capital investment!!
Anyways all the best! :]