Yea I realized that but I'm just using it as a comparison. I was planning on testing my real 1rm after about 2 or 3 more cycle's.[/quote]
Good idea. One way to extrapolate a max from a rep scheme is to keep good records. Say you do 300 x 5 in the deadlift and you can max at 350. When you reach 320 x 5, odds are you're doing right around 370, give or take. When you keep good records, it's easier to guess.
Any max rep calculator is a guess, but it's not as good as your guess from your own data.