The biggest bet of 9.8% of starting bank would worry me A LOT! At that level you would go broke with 10 losing bets (or less if the bet size was still increasing) - that is certainly a strong possibility with a 30% strike rate.

Personally I would never use a system that gives a loss of -5.9% at level stakes - regardless of the staking plan you use it is almost certain that this is going to get you in the end. Could be this is why he is selling the system rather than using it - worked fine for quite a while then broke the bank?