The "estimated" number can go up and down based on the usage over the last miles, but the (for Europe) "rated"(=NEDC) and the "typical"(=EPA) numbers are based on the battery condiiton.
This is true - apart from the "estimated" number (which is only displayed on the energy graph), none of the displayed values are materially affected by "driving style".
They can however be affected by charging habits - if you never charge to 100% then the battery can become out of balance (causing a loss of capacity that will be restored when allowed to balance by charging to 100% occasionally). If you never discharge to a low level, the displayed value can become inaccurate (either high or low). Temperature can also have an effect. None of this normally makes a huge difference, but if you are watching it very closely looking for small changes you could be misled.
Finally, all these numbers are an estimate produced by software, and the software is updated over time. So on any one car it's not necessarily meaningful to compare numbers over a long period of time. I have no reason to believe that Tesla are faking the numbers, but they have definitely improved the algorithms to make them more accurate.
For the OP's question about S85, my 2014-built S85, a 100% charge would show 245 (on typical setting) when brand new. I have seen 237 then 239 in recent months, but I saw 236 back in 2016. The numbers appear to show a moderate (couple of percent) loss in the first year or so, then little change which could be random fluctuations or could be a slow further loss.
So the OP's starting number of 240 is quite high for a 3 year old car; today's number is on the low side, but may just represent loss of balance or whatever.