ICL is on every cam card for a reason. If a calculator doesn't use it, that's on whoever made the calculator.
Their calculators are assuming the overlap is evenly split at TDC. Few people install cams there because it's rarely where best performance is found. The physics of that are complicated.
You can find cam cards or built-in advance from most vendors. Comp for example builds in 4 degrees into just about everything, but the ICL listed is just a starting point.
