Ilyce: I tell my buyers that the cash necessary to close on their home consists of three parts:  down payment, closing costs, and prepaids.  Then I break it down. 

The down payment lowers your initial mortgage balance.  If you wish, and are able... if your credit allows, you may purchase a home with little, or even no down payment.

The closing costs... are any costs having to do with obtaining financing... like credit check, appraisal, document preparation, perhaps an escrow fee, and so forth.

The third part is "pre-paids."  They are just as the name implies.  They are amounts that you, the buyer, pre-pay.  Pre-paid interest simply pays for the interest on the loan for the remainder of the days of the month left in the month in which you close.  Pre-paid insurance... pays in advance for a year's home owner's insurance.  If you have an escrow account as part of your loan, the money used in setting up your escrow account is your money... you are simply paying it in advance.

Now... I don't break this down for all my buyers, perhaps not even half of them... because, as you suggested, all they usually want to know when they use the phrase "closing costs" is what amount they will need... to close.  

By the way... I do not use the words "per diem."  I think it sounds too much like industry "lingo."      Karen Anne

Ilyce:  Selling new homes is one of my specialties.  In Fort Worth, our closings are not "round table closings" but are done with an escrow agent at the title company.  Although most Realtors usually attend their closings on resale properties, strangely enough, the great majority of them do not attend closings at the builder's title company when it's a new home closing.

I think they are missing a great opportunity for referrals from the buyer.  This is a time of great stress, and for a Realtor to no attend... is simply foolish.