1.5 or 1.6

I took the gross lift, divided by 1.5, then multiplied by 1.6 is how I got the figures I came up with. where does the valve geometry loose so much and how can I fix it? does the ratio actually behave like a 1.55 with a 1.6 rocker? does it depend on the brand of rocker? I want true lift, that is for sure, and if I have to I will just do a cam swap but that would be a shame cause this setup is new. I wanted to upgrade the rockers any way, so I thought I could get away with a ratio change to get it up to where I want it.