I was recently listening to the Best in Faction podcast and one of the guests seemed to suggest the Saim-Hann stratagem to advance and charge can be used twice in the same turn. I'm confused how this is legal.
This strat is not used in the charge phase, but rather, when the unit advances
. So, you could move two units in two different phases, and use the strat both times. Move one unit in movement phase and use the strat, then move another unit in a different phase (say, using Quicken, move one in the Psychic phase) and use the strat then. The strat usage limitation is per-phase, so you're good to go.