The higher frequency of 4x is just the respective amount for the lower #BI necessary for the top jack to reach a better advertisable 1 Mio $, the rake is entirely determined by the frequency distribution as opposed to other games where it is payed separately in advance.
That makes them a tad less variance tho which is good.
Will be very interesting to see if these get enough rec traffic to beat 5% rake, could be good for the regs if the top moves one step up