I have access to a machine bench press, the kind that has 2 numbers. For example, the number on the left is 205, and the right is 275. Someone told me that you are lifting 205 at the beginning and 275 at the top. I'm curious how much I'm benching. I don't go too heavy on the regular free weight bench press because I don't have a spotter, so when I go heavy, I use the machine. Is there a way to "guestimate" how much I'm really benching on the machine?