Diffusion error propagation from magboltz to garfield++

In Source/MediumMagboltz.cc#L3394 and following, the uncertainties on longitudinal and transversal diffusion are taken directly from magboltz (i.e. Magboltz::diferl_.dfter; and Magboltz::diferl_.dfter;). According to the calculations done directly above in #L3393, the relation between magboltz's diffusion parameter and garfield++'s is

d_{t,l}=\sqrt{\frac{2 D_{i}}{v_{d}}}

and errors in magboltz are relative to their mean value.

Following gaussian error propagation, I would expect the lines to be dlerr = 0.5 * Magboltz::diferl_.dfler; and dterr = 0.5 * Magboltz::diferl_.dfter.