The Davis VP2+ updates Solar and UV sensor readings every 50 to 60 seconds, so I'd not expect it to change more often than that. When you first open the page, you'll see the data uploaded up to 5 minutes ago in your testtags.php, then the AJAX cuts in, and shows the data from the latest clientraw.txt. The max solar and max UV values and their respective times aren't in clientraw.txt, so they only come from the 5-minute uploads of testtags.php.
So I guess it's a 'feature' .. we can only show what WD produces in the two files (testtags.php for %wdtags% and clientraw.txt which has only a limited number of variables for more frequent updates). To minimize the descrepancy, it's recommended that you upload the testtags.php on a 5 minute interval (or more often if you want, but it increases your WD FTP traffic).
Hope this helps explain what you're seeing...
Best regards,
Ken
p.s. I've added your site to the list of template sites .. thanks for letting me know!
