I have a hunch. Have you created your campaigns recently or made changes in most of your ads recently (approx a week ago)?
I've checked the data over comparable timezones (GMT-8), waited for a day, double checked, same gig.
I'll keep diggin', see what I can discover...
I'm still recording low arrivals to clicks, though the gap has narrowed slightly now to more like 27-20%.
I'm trying to reconcile the two logs (server & tracking) to see what the diff is there, maybe that'll throw some light.
Thanks for the pointers so far anyway!
I'm very curious what you will find. Please keep me posted.