I've done a few test free rolls today , and I've noticed that : client seed , aswell as server seed gets randomized after each roll. Even though I don't have the option to randomize the client seed before each roll active.
I have noticed that you are wrong. The option to randomise the client seed is here:

When you reaload the page the JavaScript calls the RAND function in your OS to create a new one. If you really want to use the same one you can just save it and change it back.
How exactly is this provably fair ? When theoretically the system can spit out any client seed + server seed combo so that the higher payouts don't pop-up as often as they should.
So this theoretical situation is impossible because our system doesn't spit out client seeds your OS does and because it is in JavaScript you can see the source code to verify that's true.
Quinn do you even know the concept of provably fair ?
Yes. I have to correct customers misunderstandings on the issue regularly.
This is no longer provably fair , you're simply asking users to "trust" you that you're not scamming them , "cause you have a lot of clients" , I find it funny that one of the most trusted dice sites here on bitcointalk , isn't actually provably fair verifiable.
I do hope you now understand that you were mistaken because I would hate to have to rely on trust. People relying on that can be easily fooled into believing trusted members of the forum who have been hoodwinked into doing the bad guys' work for them.