Why is my required embedment depth always increasing?

I am using the Hilti Profis Engineering program. I selected a ASTM Hex Head F 1554 Gr. 36 anchor, 1" diameter. I set the embedment depth to 15.75in and it tells me I need it at 16.797 in. So, I increase the embedment depth and it tells me I need a greater depth. I increase the embedment depth more and the program keeps increasing the require depth. I am placing a piece of machinery on a concrete foundation.