there is obviously a fundamental difference between adding numbers and adding numbers formatted as chars. Consider what happens when your sequence moves from 999 to 1000. In the numeric case you are still incrementing, while in the char case you are now adding new values at the beginning. So, you are going to get more block splits with char than number.

Storing values in the wrong data type is very bad practice for a number of other reasons as well, and I just don't get the attraction of it.