If you remove the mod from the game it's "supposed" to remove all the banking data. Since you are manually removing the mod yourself, I suggest that you withdraw the Sims money and add it back to the household account "before" removing the mod from your downloads folder.
Yes the mod is working as intended. But when you have several hundred households or just lots and lots of sims each with a bank account, it can be quite time intensive to manually move the monies from the bank accounts to the household accounts.
I think it would be a great feature to have an 'uninstall' option that would do the move all at once. It wouldn't help in Sandilou's case, but it would be a nice add-on in case you decide to no longer use the computers.