That could have been caused by battery rebalancing, which only begins above roughly 85%.
But if you want to make your battery live longer, you might now go back to a lower level whenever you don't actually need 90%. I prefer a longer-lasting battery over a nicer distance display any time.
I will say this every time I see this (nothing against you, just trying to stop perpetuating this [mis]information)
We have
no confirmation that balancing occurs only over 85%.
The same document primarily stated 4.0V/cell is the threshold, which occurs at roughly
73% on the screen.
The same document states that 1mV of imbalance can be dealt with every 24h period. It would take
weeks of
sitting at 90% to correct any significant amount of imbalance, and would not be suddenly corrected after a couple charges to 90%.
Weeks! before you'd notice a difference.
Many people have well-balanced packs and only charge to 80%.
If a pack truly has more catastrophic imbalance (what can't be dealt with by normal charging routines), balancing attempts at those correction rates would be absolutely futile since there's a
reason for the imbalance (something physically and/or chemically different about one or more of the many bricks in the battery), and balancing cannot correct this.
What I'm trying to say is the information source posted on these forums seems flawed from our perspective. We don't even know what percent they're referring to. For example, the 4.0V they mention is at about 88% of the total voltage swing of the battery (~2.5 to ~4.2V). Voltage does not change linearly with remaining pack capacity though, which is why at this 88% of the voltage range, only 73%
energy remains (which is what is shown on the car's display, because that's what matters). Misinterpreting this data is easy since we're not Tesla employees, and perpetuating recommendations based on a misinterpretation (or simply incorrect source data) isn't ideal.