Hi, Sunchu. The fact that more horse have won at bigger odds than 6-1 than less is probably just a blip and I wouldn’t read too much into that fact.
12 bets is a start but I would say you would need at least 100 bets before you can reach any definite conclusions. Either that or a minimum of 3 months results.
Generally speaking, the bigger the average odds per selection the bigger the sample is needed to be sure. This is because the bigger priced selections will produce less winners than the shorter priced ones, hence my opening line.
Anyway, stick with it and stay lucky.