I use to work in NYC. I was an executive assistant for the Pres & CEO and would plan our holiday parties and events for the company of approx. 600 people. I always used an event planner-same one. I have no idea what her fee was since, like another posted stated, everything was under one bill.
I would get an itemized bill from her but listed price for the space, flowers, cars, etc. I just assumed the prices were marked higher and she got something from the places we used.
Either way, it was VERY VERY helpful for me since she took care of everything. I just told her what we needed/wanted and it was done.
She always arrived at the event prior to the start and would make sure all was in order. If not, she made people jump until it was ready.
Our events usually ranged from $60,000 - $100,000.