Good question by the OP. When you listen to Randy and Corey, keep in mind that Corey's focus is archery; pre-rut and peak rut. Randy's: post-rut and late season.
Vegetation focus changes from summer to winter. Elk will focus on the high protein forbs in the summer, then move to grasses as the fall comes in. As fall moves to winter, the shrubs and oak brush become what's left over and increase in focus.
The south-facing slopes have most of the grasses and forbs but are also getting cooked in the summer months. During archery season, which generally contains the first three phases of Elk primary needs, the cows are foraging in the places with the best and most feed.
As the food quality diminishes from heat, drought, and over-grazing, the elk will move to the east northeast, and north slopes for feed since the sun is less intense on these slopes. Yes, there's timber, but there are also occasional meadows on the north slopes.
I've found forbs on the north slopes in sparse timber that was open enough for sunlight to grow forbs and grasses.