So, you're saying you are a masochist?
The problem here is the share price is determined by investor sentiment which is really hard to predict in advance. We are likely close to a "step change" in the way investors think about Tesla (meaning within a year or perhaps as long as two). When that happens the share price will probably run up unexpectedly well past your sell point. The few thousand here and there that you may have been able to "scalp" will more likely than not pale in comparison to what you missed out on. I understand you think you are avoiding that problem since you are only trading a portion of your TSLA investment but that is really irrelevant (you have to look at every dollar individually). The only way that strategy makes any sense is if you want to partially hedge your long position because you think Tesla might not ever amount to much or might be a losing investment (by reducing exposure when you think Tesla might decline).
While I agree that would have been a good strategy over the last several years (assuming you have better than average ability to time the drops and the rises), the past behavior does not indicate future behavior and we are likely entering a new phase.