Three section 6166(a) election scenarios are presented:

1. An underpayment of non-deferred tax on the return due date;
2. An overpayment of non-deferred tax on the return due date with an election to defer the maximum amount of tax eligible for deferral; and,
3. An overpayment of non-deferred tax on the return due date with an election to defer only the unpaid balance of tax eligible for deferral under section 6166..

A summary illustrates the differences among the three scenarios.