After a little reading I think I figured it out. I replalced the HD in the laptop and wanted to make sure everything was OK before I proceded without exceding my learning curve.
From the info at http://www.viztaview.com/tips/37-tips/57-sysinternals.html I ran NTFSinfo on http://live.sysinternals.com/ site and it says I have a MFT zone size of 2094MB.  All the math comes out right with JkDefrag excluding the MFT zone in the free space calculation and the Win GUI including it.
Sometimes old is gold.

Still running v3.33
Win GUI says 4.49G used, 12.1G free
Defrag log says 4.5G analyzed, 10.02G free
Both say the same total, 16.6G. How much free space do I have and why the difference?
XP, no pagefile on partition.
Do I have some drive space allocated wrong somewhere?