Salt Additions and Boil-off

Do the recommended salt additions from the primer and/or Bru'n Water account for boil-off or not?

If I follow the primer suggestions and add 1 teaspoon each of gypsum and calcium chloride to each five gallons of water used (or 0.2 teaspoons per gallon), do I have to account for my boil-off rate in any way? As a very simple example, I'll ignore grain absorption losses and deal only with boil-off volume losses. I start with 6 gallons of total water volume so I add 0.2 teaspoons per gallon of each salt (gypsum and calcium chloride) per the primer. If I boil for one hour with a boil-off rate of 1 gal/hour, then I end up with 5 gallons of wort containing 0.24 teaspoons per gallon of each salt (0.2*6/5=0.24). However, if my recipe calls instead for a 2 hour boil, I end up with 4 gallons of wort containing 0.30 teaspoons per gallon of each salt (0.2*6/4=0.30). I see that Bru'n Water has a total batch volume cell on the Water Adjustments tab, but it is only used for color estimation.

I assume I have to add salt per gallon of total water used and not the final water volume since salt additions, in general, can be used to adjust mash pH - that is, the salt content prior to boiling is important. The salt content of the final wort/beer is then just a function of my boil-off rate, and I shouldn't worry about it.

Thanks in advance!

As with any water source, the ionic content is ultimately concentrated by boiling the wort. Since there are many factors that influence what those ending concentrations might be, its easiest to base your beer results on the starting water concentrations. For instance: you like they way your pale ale tastes when you started with 200 ppm sulfate. It doesn't really matter that the boil concentrated that sulfate to 210 ppm and some sort of fermentation loss took 20 ppm out (I'm making that up since I don't know what the ending concentrations are).