There is no dispute in the math it's 60/40 in the players favour on each single spin after the initial spin from 8. What you need to remember is the odds roll. From the first spin to get to 24 is a 1 in 10 chance. However, if you get enough scatters to start at 20 then the single gamble is 60/40 in your favour, these are the hard stats for getting 24 spins:
0.5 x 0.6 x 0.6 x 0.6 = 0.108 or 1 in 10