why toilet paper roll on top vs bottom -- a usability geek's explanation

I use to not be able to articulate why the toilet paper roll was better to roll from the top vs the bottom but I recently came to a very Jakob Nielsen heuristics explanation that I can use the next time this age old debate comes up. ;)

Simply put, Heuristic 1: Visibility of System Status.
With the next paper roll sheet coming from the top, the user can quickly, visibly establish where to grab for the next sheet. Whereas roll on the bottom, user needs to look harder, maybe even rotate the roll a full cycle, and look for the sheet often hidden at the back of the roll, towards the wall instead of facing the user.
Why is the next sheet most often laying visibly at the top of the roll, you may ask? The physics of tearing a toilet paper roll at the 'average speed' when rolling from the top naturally lands the next sheet at the top of the roll. When roll is at the bottom, the physics of tearing often leaves the next sheet by the back of the wall and hence more hidden from toilet paper user.

Now because toilet paper user can easily see the state of where the next sheet is at when rolling from top, we also automatically earn the following heuristic: Error Prevention. We prevent the user from having to roll or look behind for the next tp sheet to tear as again it is most often visible at the top of the roll.

Aren't Nielsen's heuristics so much fun when applied to non software contexts?! :)