Thanks. Yes, the "last tx..." part was just an idea only to be absolutely sure the amount in balance is coming from a recent transaction, as a secondary check. I know every xpub can generate billions of addresses in the M84/0/0/X path. But since in some cases I project to be using an exchange account (that generates different addresses) I cannot verify nor obtain the xpub they will be using. In most cases however I will be using a regular xpub so I will be sure to use a fresh address always.