下面有條友咁講
According to my calculations 100% S&P has an expected CAGR of around 5% + risk free rate and a 50:50 mix of UPRO has a CAGR of around 5.6%+ risk free rate. Simply put, even if your timing strategy switched between UPRO and S&P at random, you would still expect higher performance than 100% S&P.
The performance differences you are seeing likely has nothing to do with your timing strategy but everything with taking more risk. This is clearly visible in the screenshot because you outperform the S&P 500 while taking twice the amount of risk. Higher risk results in higher reward (as long as you don't pass the kelly criterion), who would have thought?