I add improvements any time I feel the benefit the program. I keep a file for people to read at the group called ongoing programming. In the file I've tried to explain the difference between an improvement versus a disaster.
I have run into people who feel there is no change except to fix a disaster. At some point they will have to confront the real-time test, wherein I have been making program improvements all along.
I'm avoiding discussing any results before the real-time test. I feel it can and will make the same statement but will be based on publicly recorded data, rather than a backtest.
You CAN time the market!
But only after you trash the big 3 myths.
Myth 1 - its possible to get every point of every move
...Myth 2 - you'll never have a drawdown
......Myth 3 - you'll never have a loss