Quote Originally Posted by FuNkY_CaPrIcOrN
I am glad you asked this about reference numbers.Because I have always wanted to know about this.

What does Automatic Numbering mean anyway when you go to Preferences.....Numbers?

What does Style and Width do?Assign Reference Numbers to new Albums?What does it all mean? :-/
OrangeCD can automatically generate a reference number for each new CD or LP album. It is easier to think of this number as of physical location of CD on a shelf. Style and width settings define how this number will look. For example, it can be "0045" or "D-0045" or even "rock-0045".

Note the numbers are automatically generated for LP and CD albums only. No MP3s.

Renumber feature does exactly what it is named after - it renumbers the range of albums according to the selected style.