Having received my paycheck I was able to figure out what went wrong (or "right," if you want to look at it that way) with today's paycheck. The reason I have more money in this paycheck is because I reached the maximum allowable deduction of $12,000 for my 401(k) plan on the last pay cycle. Having hit that maximum Payroll halted the deduction and rolled the money into my regular deposit. This is cool because it means I'll get some more "extra" cash coming to me on this year's final paycheck as well, yielding a total unexpected windfall of over $800! Woohoo!