Michal, 80% S/R and 19% POT is fantastic. Whilst I can manipulate my plan to achieve 80% S/R ,the number of bets diminishes dramatically as does the average divi, and my POT stays around 4%. So I go for the better turnover.

In your case I would have a look at how the plan has fared say over at least 2 years if that is possible, but I would still only bet at level stakes. If you get bored you could run a seperate bank of 5 units and bet 20% never reducing, always stop if there is insufficient funds to place that last bet, and start again with a 5 unit bank.
This will give a lot of fun, and some interesting winning runs, with very little damage should you hit a bad run. But remember only on a small scale, keep your main bets at level stakes.