This still doesn't incorporate the time the DelSig ADC itself needs to settle. The component data sheet specifies the "startup time" as "4 samples". And when looking at the "single sample" mode, this is the time which is needed for the initial conversion.
Excellent point. Also does not include -
1) Settling time due to transducer/source effects
2) Settling due to PSRR effects
3) Settling due to thermal/triboelectric/...... effects
As stated prior oversimplified. So much settling, so little time.....