Ok, all, I REALLY appreciate the comments back. Learned quite a bit in the exercise. In this case, they guy who's taking over for me is a real PL/SQL (Oracle) nut; I read this thread, and liked it best.

I urged him to make use of it, and he tried it out, kinda liked it, but opted to use an Oracle function to handle the time shift and write a simple Perl piece that used ranges to give a proper time range. The range is based on whether or not we are between the first Sunday in April and the last Sunday in October or not. It, admittedly, was simple, but isn't the most efficient solution (of which I think BigLug's probably is).