Panasonic phone replacement batteries

I have a Panasonic phone model number KX-TGA430B. I was looking to replace their batteries as they lost most of the juice. The official documentation recommended to only use Panasonic rechargeable Ni-MH batteries with codes HHR-65AAABU or HHR-4PDPA with 630mAH min. These branded replacement batteries are expensive. I instead bought a set of AAA Sony rechargeable batteries with a high capacity of 900mAH and NI-MH and they seemed to work just fine. Just make sure that any set you buy is Ni-Mh and has a min of capacity > 600mHAH.