I see little point in cutting and pasting since the resume and the application play distinct roles. The employment section on the application is best for the brute facts of employment such as dates, location, and duties. Since you control the format of the resume, you can make certain that it covers crucial details that are missing from the application such as major accomplishments in each position, how many workers you led, how large a budget you managed etc. Just make certain that the information on the two documents is consistent (applicants have been known to mistakenly include different employment dates or provide different titles for the same position).