My interpretation of the book is that you don't need to do the lax tea at night if you do the SWF (Salt-Water-Flush) every morning, although the book is somewhat ambiguous. What *is* required, unambiguously, is some sort of elimination every day, whether that is SWF (Salt-Water-Flush) or lax tea.
I think it is fine to do the lax tea at night and the SWF (Salt-Water-Flush) in the morning if that is the way you are doing it and it works for you. I personally don't like the lax tea because I get cramps so I usually do just the SWF.