Hay, same concern ko dati sis! Avent discontinued yung 9m++ with 5 holes kaya sobrang hassle, lalo na kung aggressive chewer ang baby like yours, tried asking sa Pureen and other brands kung may similar flow level pero parang Avent lang talaga ang exact match. One of my mum friends eventually switched to Tommee Tippee or MAM teats na nag-recommend ang pedi niya, pero honestly parang adjustment lang talaga for the baby so you might need a few tries pa; some moms go back to buying Avent 6m+ and replacing them more frequently kung daw talaga sila mas naka-hold up better sa biting.