What do you mean more specific? Those were directions a 4 year old could follow.
Okay..
1. Make a new folder on your desktop.
2. Copy your npc data file.
3. Paste it in the folder twice. (Rename one of the files, then change the name back later.)
4. Edit one of the npc files in the folder to double exp.
5. Paste it in your data folder in Seose when you want to have double exp. (Do not delete the one in the older folder)
6. When you want normal exp back, paste the other file.
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Hail Satan!