Before revision:  In this paper, we investigate the extent to which FP and ES can differ, characterise tree shapes on which the indices are identical, and provide a new, shorter proof that FP and SV are identical on rooted trees .
After revision:  In this paper, we investigate the extent to which FP and ES can differ, characterise tree shapes on which the indices are identical, and provide a new, shorter proof that FP and SV and its implications in more detail .