Well, i think you missed something. there are a few save slots, i do not know which you use, i think all save slots data are inside .qt file and you need not to forget to delete Local Storage folder in AppData which is indicated inside guide. There also can be a few id's with money, you can change both of them. I have played and cheated my save file recently on version 1.7.0 and everything worked fine.
1. cheat your save with notepad ++.
2. save changes
3. delete Local Storage in AppData(see in guide exact folders)
4. Play with cheats
P.S. And if you want to use others save files, you need to rename them with name of yours. and delete bacckup in AppData