In this article by Pat Kelly he says the correct way of figuring the DCR is by using the cams advertised duration. That using the .050 reading is incorrect. But KB calculator is adding 15* so IDK who is right. I wish I had found these articles when my engine was on the stand so I could check for myself. He also says if the DCR should be in a range of 7.5-8.5. If it drops below 7.5 like you suspected the torque drops off and you also lose power on the top end. If it is in a higher range tha 8.5 no problem add racing gas.
Dynamic CR