  In 2011, a discrepancy between the values of the Planck constant measured by
counting Si atoms and by comparing mechanical and electrical powers prompted a
review, among others, of the measurement of the spacing of $^{28}$Si {220}
lattice planes, either to confirm the measured value and its uncertainty or to
identify errors. This exercise confirmed the result of the previous measurement
and yields the additional value $d_{220}=192014711.98(34)$ am having a reduced
uncertainty.
