I am doing nozzle reinforcement calculations for a 8" ID, t=1.125", in a 36" OD semi-elliptical head. The nozzle offset is 3.0" and the angle is 90 degrees. Per Section UG-37(a) and the Codecalc manual, the thickness of an elliptical head is analysed as equivalent spherical head with a radius of K1D. However, Codecalc 6.20 does the thickness calculation using the formula for an elliptical head per App 1-4(c)(2). Shouldn't the formula for a spherical head from App 1-1(a)(2) be used instead?