I see what you mean and to be honest, the rules might be explained in more detail if my theory is right.
A winning streak can't be lower than 1.50, but can be as high as you want.
A losing streak can't be higher than 4.00, but can be a low as you want.
By winning that one bet, you discontinued your losing streak and started your winning streak, which was then broken by the next lost bet.
I get your theory, but it is not spelled out that way in the rules, which explicitly state that bets outside of the criteria do not count either way.