There're two possible locations for xdb_wallet.
Single-instance Databases
The root entry of xdb_wallet is $ORACLE_BASE for single-instance databases.
$ORACLE_BASE/admin/<DB_UNIQUE_NAME>/xdb_wallet/
RAC Databases
The root entry of xdb_wallet is $ORACLE_HOME for RAC databases.
$ORACLE_HOME/admin/<DB_UNIQUE_NAME>/xdb_wallet/
That's the difference.