My question is about the physical presence of this statement : "When traveling to the United States, the primary (or principal) applicant must enter before or at the same time as derivative family members with visas."
My example, The principal applicant enters the US in Jan 2020 as LPR. The parents files for children, that gets approved. Now the children are ready to enter the US Feb 2023. If the principal applicant is out of country during Feb, my question is the principal is required to be in the US at the time the children arrive? Or because they have been in the US, the parent is considered to have entered the US before or at the same time as the derivative family members?