there, i install Wp Smush Pro on one of my website

Hello there, i install Wp Smush Pro on one of my website and activate Super Smush.

But i dont feel it's really more powerfull than lossless, indeed i only get few Kbs off when Lossless sometime cut the file in half. So why Super Smush with lost quality dont get ride of a little bit much ? i remember getting much better gain on some of my other websites.

Cheers.