Part of the problem is that Tesla doesn't really collect enough data about the user's utility plan and rules to truly optimize it. In order to make a really good optimization, I believe you would need both the grid consumption and grid export price for each TOU period. This could encapsulate things like lack of net metering, non-bypassable charges, etc.I don't understand why Powerwall would behave this way. In Cost Saving mode, one would expect that it will try to maximize the saving. That means, it should provide max power during the peak period. Not provide power during off peak, and run out of power during peak. That sounds contrary to the name "cost saving mode". In fact, that behavior sounds more in line with "balance mode", where the main concern is to stay off-grid as long as possible.