However, if the ungrounded conductors are increased due to voltage drop, you lose the curve that is built into NEC Table 250.122 for reducing the size of EGCs due to 250.122(B). Section 250.122(B) ...

A. Equipment grounding conductors of the wire type must be sized not smaller than shown in Table 250.122, based on the rating of the circuit overcurrent device; however, the circuit equipment ...