Ken is a self-employed architect in a small firm with four employees: himself, his office assistant, and two drafters, all of whom have worked for Ken full-time for the last four years. The office assistant earns $30,000 annually, and each drafter earns $40,000. After deducting all expenses and one-half of self-employment taxes, Ken's net earnings are $310,000. Ken is considering whether to establish a SEP plan and has a few questions:

1. Is he required to cover his employees under the plan? Why? Or Why not?
2. If his employees must be covered, what is the maximum amount Ken can contribute on their behalf?
3. What is the maximum amount Ken can contribute for himself if the employees are not covered?
4. If Ken is required to contribute to his employees and chooses to contribute the maximum amount, what is the maximum amount Ken can contribute for himself? (Hint, calculate the employees' amount first), Ignore any changes in Kens self-employment tax.