Burley,
All I can figure is that something is bumping up against the plugin and stopping it from calculating the time. When I had you run that template change you should have seen an output like:
You should be seeing XXXX - YYYYY
But the XXXX part was blank, thus there is no time for the system to check against.
Try modifying the plugin for the hook global_start as follows:
If this produces a result in the first part of the template change I provided a few posts back, then try using
If that too produces a result let me know.