Yobuck's absolutely right. I've been long range hunting for 20 years now and we never needed a cosine indicator. We were shooting at about a 20 degree angle down hill. At that distance I just took 2 clicks off. Robert hit exactly where we had discussed to hold. I agree shooting uphill or downhill does have an effect but under 1000 yards and with enough experience you just know how much it will effect the impact.
As for the bears in the tree they were pushing the 2300-2500 yard mark, and I'm firing my spotters, they couldn't see a damn hit. I won't even mention the shots at 1500 they couldn't see