$SPY Monthly Chart with MACD Crossovers Says "Risk Off"

MACD crossovers on the monthly chart have been a reliable indicator of impending trend change (long term). A downward crossover happened last month, indicating that the odds of a correction have increased. For me, it means "Risk Off" until I see an upward crossover. Until that happens, I will be in cash. Consistently using this long term indicator would increase returns beyond simple buy and hold.