There is no extra charge for multiple QuickBooks files. With the Swizznet QuickBooks hosting and online accounting system each user account can have as many QuickBooks files up on the system as they need. We do not monitor the quantity of QuickBooks files you have uploaded on the system and many accountants put all of their QuickBooks files up on the system so that they can take advantage of the continuous off-site back up, security and the ability to access it from anywhere. Our pricing is per user account and is not based on how many QuickBooks files you store on our system.