sleddman - I think you should test again. The drop figures don't work very well in my opinion. 1 1/2"high at 50 puts it about zero'd at 70. On the other hand, 6" low in the next 30 yards at 100, but only 2" low in an additional 30 yards after that is not reasonable? Maybe I'm missing something. The top of the back hold for a centre hit is about right, however.
I think you'll find the drop at 100 is closer to 3 1/2". Dropping another 4 1/2" to 5" is about right for 130yards with that light a charge, I'd guess.