Hair closest to the scalp processes faster then the ends due top the heat coming from the scalp. To prevent overprocessing, applying relaxer to the ends first was 100% correct. Keep in mind that the next time she does her touchup that there will be some overlap. So those texlaxed roots most likely be straight after her touch up is complete.
This paricular rule is true for all chemical processes. Shamboosie discusses it in his book. When I colored the front of my hair last it was strongly recommended that color be applied to the ends first to ensure even application and prevent "hot roots" aka very bright roots..