I checked my numbers, and I had stupidly entered the dollar result rather than the percentage profit. Here are the real numbers:
4H DAILY
10, 21 1473% 1582%
11, 21 1509% 1586%
12, 21 1531% 1714%
13, 21 1412% 3056%
14, 21 1279% 2813%
15, 21 1395% 2833%
16, 21 1550% 2698%
17, 21 1663% 3251%
18, 21 1555% 3174%
19, 21 1990% 3074%
20, 21 1990% 3376%
The best number I've found so far in my experimental meanderings has been the 21, 22 on the daily chart: 3555%!
I'm pretty sure there's something wrong with those results. Look at the chart yourself. Daily EMA22+21, around April 2013:
There is either no meaningfull crossover at all (lines run in parallel), or an incredibly late sell signal following the crash.
I suspect the numbers you get are an artifact of how the gekko simulation calculates crossover... maybe if the averages are that close together it breaks apart.
I admit, what I would expect the simulation to do in that case is to either get almost no trades (in which case it should be the same result as buy&hold), or a huge amount of trades (in which case the trading fee should destroy all profits). So I can't really explain the numbers. Either way, I'm really sceptical.
EDIT: maybe there's a small chance the numbers are right after all.... during the 2011 bubble, this method would have performed pretty well. sell signal after the peak came late, but buying back would have been at a pretty good time. In other words, it could have outperformed buy&hold during that time by an order of magnitude.
Again, apologies that I can't run any tests myself, only have a netbook with me right now, but can someone run just the 1d EMA22+21 test from January 1st 2013 to now? Buy&Hold for that period would have been around +676%.