OK, thanks. Part of the problem is my inability to explain myself clearly and the lack of information about my set up. I only have one pot. So, I batch sparge into a pail while the sparge water is getting to final temp. Then, after I've collected all the first runnings, I put the sparge water in and dump any excess I have. I then add the warm first running to the brew pot and begin heating while I sparge the 2nd runnings. These then get added to the pot. I don't have the flexibility to add all the wort at once.
So, I am going to add my FWH to the plastic pail that I use to gather my first runnings and then move them to the boil kettle while I get my 2nd and go from there. Originally, I was thinking I'd add them when I started to heat the first runnings.
The other problem is that I brew while I work so if I get a phone call or something, timing can be disrupted. Not ideal but it works.
I just wanted to be sure I understood that these were a flavour addition. It's just a little counter-intuitive based on what I learned 20 years ago about flavour and boiling. I'm gonna give it a go.