How many gambling sites are you playing and do you use the same strategy? I'm playing on at least 4 sites now and uses a different variation on the martingale and some guessing method and I found out that I have good success implementing a method on one gambling site that is not effective on other gambling sites, how about you?
I only gamble in one bitcoin casino since I do not see the point of gambling somewhere else when I had never had any problems with the casino I am currently using, so unlike you I do not have the chance of trying the same strategy over different casinos and see my results, but logic dictates that over the long run you should see the same results since no strategy can alter the nature of the games, and this is even more true for martingale which has been proven time and time again as a strategy that does not work.