Format of listing

Aaarrgh! I just validated a file, and it passed. But, the source 
listing, which I indicated I wanted, had no format, i.e., all lines were 
left-justified, no offset and nesting of items. Now, I validated a file 
just two days ago and the listing format was with the indents that were 
in the file. Why the difference?? That listing is to me the best way to 
keep a copy of the page [a template] and without the indentations it is 
difficult to read and understand.