  The one string-loop correction to the energies of two impurity BMN states are
computed using IIB light-cone string field theory with an improved 3-string
vertex that has been proposed by Dobashi and Yoneya. As in previous published
computations, the string vertices are truncated to the 2-impurity channel. The
result is compared with the prediction from non-planar corrections in the BMN
limit of $\mathcal{N}=4$ supersymmetric Yang-Mills theory. It is found to agree
at leading order -- one-loop in Yang-Mills theory -- and is close but not quite
in agreement at order two Yang-Mills loops. Furthermore, in addition to the
leading 1/2 power in the t'Hooft coupling, which is generic in string field
theory, and which we have previously argued cancels, we find that the 3/2 and
5/2 powers are also miraculously absent.
