I thank you very much for your well thought reply and coding of this script.
I have installed on two sites...One ran just fine and I found the birthday greetings as expected. The other site has not run it as of yet and the date is still yesterdays in the timetick area. TO see if it would help...I have changed the load setting to be 5. So...Now I am just waiting to see if it catches up.
BTW...Boy is that load setting kinda confusing. Could you not have made it easier and said "If server load is less than X" and use a real server load number.

The default 30 number means nothing to me.
Oh..yes...Does the above style hack replace the other one you mentioned? If so...their does not seem to be any code to put back the users real style at the next move. (Though the above is much easier.) (I am glad you liked the idea.)
(Note...everything I do on our site I need to be concerned with on loads. As mentioned, 30,000 unique visitors a day...12.5 million page views a month.)
David