If OFX Web statements are placed in the wrong account, blank the
Financial Institution (FI) for the *wrong* account in account
settings. Do that in the Account Settings/Details, which you can
reach by right-clicking the account name on the Account List. Don't
just change the FI. Blank it.
On the Account List, if there are transactions to read for the
wrong account, right-click TransactionsToRead, and then click
Import the OFX file. Money should ask which account to use. Tell
Money the statement should go onto the right account.
Put the FI for the *wrong* account back.
If that does not fix it, see method 2 of
change the currency of the wrong account.