In the words of my teacher, “the True nodes are hardly true”. Mathematically True Nodes are an elaboration of the Mean Mode calculation, and whilst it is presented in the work “Sūrya Siddhānta”, the True Nodes were not employed in the same work to display chart calculations for Jyotish reading, but instead for the ascertainment of eclipse occurrences. Hence Traditionally, True Nodes are not used. Instead, Mean Nodes are.
Another reason presented for using the Mean Nodes as per the tradition is, that True Nodes oscillate between retrograde and direct-motion. This breaks the paradigm of the Jyotish philosophy in that the Luminaries are always direct, the Nodes are always retrograde, and the five remnant Tara Graha oscillate between these two states.
A node in direct motion goes against the nature of the nodes! My experience is what convinced me of the accuracy of this, and whilst I encourage everyone to examine this on their own, the advise of the Tradition is to employ Mean Nodes in chart examination.