There is no real way to compare DIRECTV's Ka capacity with Dish's Ku capacity. DIRECTV's Ka capacity you can think of as an array of tiny overlapping ovals covering the US, think of a honeycomb. They were satellites meant for internet access with transmitters going up from under each of the ovals. They were adapted for TV usage (just one uplink per oval).
They can map DMAs by picking which ovals get the signal for each DMA, but they have to have the same channel on multiple frequencies since the ovals overlap. Which means that they use up more capacity for a local channel since they have to use multiple channels for the overlapping ovals to cover a DMA. Dish uses one spot and one frequency for a local channel. To do a national channel on Ka, DIRECTV in a sense sends the channel down in every spot. Since the spots overlap, they have to send the channel down in several frequencies (I suspect 5).
DIRECTV has the advantage of a fine granularity of the spectrum usage, Dish has a standard of 32 frequencies, each of the transponder frequencies then carries multiple channels.
Ka band is also 1GHz where Ku DBS is 500MHz, so 2x the bandwidth. But Ka is a higher frequency making for more rain fade, so needs more error correction, more power or a larger dish.
So, in essence it is really hard to compare, DIRECTV has more satellites and bandwidth, but they are forced to repeat channels multiple times tying up more bandwidth. Dish has less bandwidth, but much more efficient use of it.