"The Proposed Regulations go on for over 100 pages. However, among the more critical (and complicated) provisions ... are those providing extensive rules for the attribution of deferred compensation, non-qualified plan benefit accruals, equity-based compensation, and even severance pay.... [U]nlike the other provisions of Code Section 162(m), the determination of whether the $500,000 deduction cap applies ... is made in the year in which the individual performed the services, not in the year the amounts are actually paid."