I am like Crusty and I ignore the losses to trub and chiller.
IMO this figure is useless at the home brew level and really just goes to cause confusion when a newby is setting up Beersmith 2.
In a commercial situation it becomes a lot more relevant as this figure will come into play with your profit (or loss) factors.
In the HB situation as long as you achieve the amount of beer you need to fill your keg or your required amount of bottles then that is really all that matters.
Many BM brewers let the trub settle out and can gain a litre or two of wort for starters or just add that wort to the fermenter during fermentation.
This, of course, is only my opinion
Cheers