In the function of r2eff_read, in data module of the dispersion, added the possibilities to read
r2eff values which are replicated.
This is done first checking if the dispersion key exists in the r2eff dictionary.
If it exists, continue add 0.001 to the frequency until a new possibility exists.
This should help handle multiple R2eff points, as separate values and not taking any decision to average them.
