In the Lifco edition of Nityanushtanakramam, in the section about Sandhyavandanam, it is mentioned that after reciting the achanamana mantra which starts with “achyutAya”, one must partake tirtham twice and recite the twelve anga Vandana mantras which starts with “keshavAya”, once; But in the Sandhyavandanam PDF version that is released by Sri Sundarkidambi with the blessings of Shrimad Andavan, available at www.prapatti.com, it is mentioned that both the achamana mantras and the anga Vandana mantras must be recited twice; which of the two must we follow.