PaulRB:
So... does your code work or not?You don't need to worry about the 5V vs 10V thing. The input to the voltage divider is 0-10V. The analogRead() gives you a corresponding value 0-1023. The fact that it went through a stage when it was 0-5V is irrelevant.
oh, really? 
I didn't know that, as I said, I'm super new, basically just read a bunch of other forum posts that all said something about only 0-5v, like this one Arduino Mega 0 - 10V analog input? - Electrical Engineering Stack Exchange