Question about employment section - listing multiple positions at one job

A number of applications require completion of an employment section in addition to uploading a resume. They allow you to fill out the company, position and months you were there, but if I had multiple positions at one company should I list all of them? It looks a little silly to have the same company listed three times in the summary, but I also don't want to just put my most recent position and have it seem like that's the job I've had since I started. Thoughts? The position section is optional, but would it be unwise to leave that blank?