I am attaching another link to show you what I get when following your instructions.
http://imgur.com/TfFNem5

"X" marks the starting point for the first selection of cells, the cells numbered 1-4 are the second selection of cells, and the cells numbered 1-8 are the third set of cells selected.

I cannot, as you say, hold the "shift" key and select anything to the left of my starting point, as in a continuation of left and right together from starting point. I can select either directly left of starting point or directly right of starting point just as before. Holding the "shift" key has no effect.

As to the numbers updating, I don't know how that could be done. As you can see I have three separate numbered sections.

Also, the double digit numbers do not want to center within the cell, rather they want to align "right" with the single digit numbers.