Yes, a very correct statement for Efke/Adox CHS.You must beware of over exposure with EFKE films that causes increased grain and loss of sharpness. These a re single layer emulsions and have a bit less tolerance to under or over exposure.
But Rodinal is not a real fine grain developer. But high acutance developers are fitting very good with Efke 25-50-100 films. Like Tetenal neofin Blau/Blue, Beutler A+B or FX-1.
So if you want less grain: Try the Efke 25 in one of those developers.
And when using Rodinal, go to less agitation because then Rodinal will generate much less grain too.
Here an example of Efke 25 in Beutler A+B, 1+1+10 for 7:00 minutes, 20C in 35mm format.