For a lot page, it tends to start to count from the lot's left top away from the road. This is also true to floor tiles.

If I didn't misunderstand what she did, she might have used the lot expander in base game configurations to expand some empty lot templates Andi8104 released on this same thread and surely alter the lot zones for the community ones.

BTW, for lot re-zoning, there're 3 major ways to make lot templates for all EPs and the base game.
1. cheats under EP1 UNI without UNI content. (simplest & easiest)
2. mod the neighbourhood package as Andi8104 had shown. (not hard)
3. lot file replacement with a community lot of the same dimension specs. (easy)
Only the first method requires EP1 while the other two do not take any EP to switch the lot zone.

Newly created lot basically has no specific data but just the basic format and data copied from the lot template.

Well, I wish I could dig into it but my another game copy is still on the make (a new OS copy + defrag + new installation + etc)