Cisco Call Manager 6 CDR polling Config/Assumptions-  interface to 3rd party call processing file accounting

Hi

I need some help with confirmation/recommendations on the below assumptions when developmenting for the Cisco Call Manager 6.
The below URL outlines the various methods of CDR polling that I understand are compatible with Cisco Unified Communications Manager 6.0;
http://www.cisco.com/en/US/docs/ios/voice/cdr/developer/guide/cdrover.html  

If the File Accounting method is chosen, and the below configuration settings programmed;
maximum cdrflush-timer = 1                    (1 minute)
maximum buffer-size = 6                        (6 KB file size)
maximum fileclose-timer = 60                 (60 minutes)

QUESTIONS
- Will the fileclose-timer lock the file for 60 minutes, although we have requested flushing every minute?
- Would these options create a new file every minute of the day?
- What if, when no calls have been made for the time period? (Is a file of zero KB created? )

With these configuration settings we would be looking at connecting to the FTP server every minute, download the new file, process the file to the students account, and then delete te file from the FTP server.

Any assistance would be helpful

Cheers
Chad