Q: Does Odeon have T20 - and how does it calculate RT?

A: T20, T10 and several extra parameters will be available from version 11.
The reverberation Time T30 and EDT was selected from the beginning as these two reverberation times is enough to know the room acoustics. However, T20 and T30 are both calculated in the Global Estimate. and from version 11 it will be possible to calculate T20 and many other acoustical parameters in point responses as well.

Reverberation time, (T30) is derived from -5 to -35 dB of the backwards Integrated energy curve according to FDIS 3382-1[6]

See below how you can analyze the decay curves from a point response in the Auditorium or Combined edition. The point response shows all curves in the 8 octave bands, to investigate decays curves in a single octave band further press A. By zooming in on the backwards integrated energy curve (E, Integrated) you can analyze different steps of the decay e.g. to see how calculations of reverberation time based on different intervals of the decay curve give different results.