yes. i do think you missed something.
if i run the new ping sampe code i get a minimum error of 1cm or 2cm even in an absolutely stable setup, if i change the calculation to float the error is a little bit smaller but still in the range of 1cm. and both will give no stable values. the results fluctuate with ever line on the console.
if i use my 'slow' method to measure i get an error that is in the range of 1mm and absolutely stable values. no fluctuation. repeated measurements give the same distance again and again.
this is a huge difference for my application. and now it makes sense to appy the temperature correction.
if you say that this is not your intendet usage scenario that is fine with me. but to say the sensors are inherently so bad that nothing can be done ist just plain wrong.