@mark.dickinson:

You asked some questions, then, I also asked you about solving this problem. It seems to me you just love to talk.. I just answered to your questions. If "this isn't the right forum for that discussion" as you mean, it concerns you too. When you ask it's right, but when I answer it's wrong place to discuss ?! I can change this line of my post - "In this case, whatever the range the full right result is a return" to " In this case, sometimes right result can be return like a round". round function also not work properly, my_round too. Each of them must be used in its place. In the end I wanna say that, if you want to discuss this further,  please, we can continue conversation in mailing list or where you want. Thanks.