You really got 100K reward points only from the HI-LO game? that is some heavy betting... 0.5BTC so I don't really understand why you needed to exchange the reward points in order to withdraw funds, if the withdraw threshold is 30k satoshi...
Not really, I think I've frequently gotten the 100k levels, if I remember well at least 400k satoshi exchanged from RP, and I take the rewards bonus promotion during 3x, 4x or 5x to help me get there faster.
So at 5x, you really are just trying to get 20k RP which isn't at all impossible.