Lord Sirf
be aware that when you bring to yellow one bg still can remains the half of balur hordes inside it
so from yellow you are supposed to find since the half of the total hordes till only 1 troop of balur remaining
i can suggest you to control the remain troops inside tracing the total xp you got in each hit
RegardsI often find a yellow offense bg takes more than you think it should. We can't see whats in it like a defense bg and if you are not sending the "best" units to the bg it will take more. I am sure you know this already though :)
I think occult would have been the better choice for that particular bg but its hard to tell for sure without the test run of 15 pikes.