Just found your class after a user pointed it out to me. I'm interested about why you didn't just alert me to the bugs in my class? Certainly there were a couple, but they were easy to fix, of course. The original class is updated on PHPClasses if you want to try it out.
It's not a very quick class to write, is it? The crontab scheme is a bit more complex than it first appears. Anyway, thanks for crediting me with the idea. I'll download your class and compare it with mine. Perhaps there are some implementation ideas that I can feed back into my own development.