.25 What's Your B.C.# for The K.O.?

[Pumacarl]

I was shooting the .25 K.O. slug today, first at 160y flying nap of the earth, and next from 100y, and I did not get the same B.C. results. By "nap of the earth" I mean that my target was almost out of line of site being mostly below a high spot in the field. Strelok Pro tells where and at what height your round travels so I made use of the info. I am wondering if shooting a round that close to the ground changes the B.C.? I went to set the target to be a little higher up and when I crested the slightly elevated ground (I wouldn't call it a hill) there was a woodchuck eating 15y off to the side of the target. The target was hanging steel plates, which I had been ringing, and he did not run for his hole until he actually saw me. I did not expect that! Anyway, I figured my B.C. at 160y to be about .07, but at 100y it was much closer (actually higher) than the stated .09x number on the tin. I'm curious what others are figuring their B.C. to be with this slug? I've never noticed a B.C. change that much, usually I run the same number. I think there might have been some aerodynamic jump/drop going on, because there were some good gusts of wind today too. I probably shouldn't have even tried to calculate it today. I feel like I wasted a tin of slugs.