On the electric shifts you could, but that .69 is brutal, the shifts are better thru the main box. The A518 ratios are
2.45-1.45-1.00-.69od with splits od
.59-.69-.69
splitting gears you would get.
2.45-1.69-1.45-1.00-1.00-.69 split gears in red.
and I have no idea how much power you could jam thru that planetary overdrive