Just to touch on the new GHB19. Remember, in the old GHB18 you received an additional command point for each increment of 50 points you were under by. This let you run under points, get command points (at no point cost), and potentially get the triumph table benefit.
Now, you actually spend 50 points counted in your army's point total. (and at a maximum of 1 CP as mentioned above)
With the new edition, I am at 950 and wish to take an extra CP... my list total is 1000. Old edition, I would still be at a list total of 950.
In addition, you don't accrue your inherent CP or your extra CP until the start of your first turn (small change, but big implications). This is big for those who like to go second... you will have not command points to stave off bad battle shock test from a heavy alpha strike.