Aside from importing your Customers into Commit, the Commit-QuickBooks Link includes many other useful functions.
You can view all of the synchronization options that are available between Account records in Commit and Customers/Vendors in QuickBooks in the Accounts window under the QuickBooks drop down toolbar menu.
There you will see one of the following two menus:
The first menu is displayed when a selected Account is not linked to the parallel Customer/Vendor in QuickBooks.
1. 
The second menu is displayed when a selected Account is already linked to the parallel Customer/Vendor record in QuickBooks.
2. 
All the options are accessible from the Accounts window, so it is not necessary to open the QuickBooks Company while those actions are being performed (although if QuickBooks is open you may notice performance improvements).