For the year ending 30 June 2016 Jonathon Nguyen, an accountant lodged his tax return on 30 September 2016 and received a notice of assessment on 1 November 2016. He failed to include consulting income as a CPA trainer of $4,500, and claimed full costs of $5,500 for a recent trip to America. Whilst overseas he consulted with accounting firms for half the time and enjoyed sightseeing the remainder of the time. He also claimed costs for part-time secretarial services performed by his wife Cynthia at a rate of $50,000 pa. However as a result of an audit Nguyen received an amended assessment on 1 February 2017. The amended assessment included the omitted income and reduced his allowable deductions in relation to the overseas trip and the payment to his wife by half.

1. Advise Nguyen of what course of action he may take to object to the amended assessment, and the procedures he must follow?
2. What are the time limits which apply?
3. What penalties may be imposed on Nguyen?