In that case, my bad. What I was referring to was the fact that if I log into my router gui then the reported downlink SNR constantly fluctuates (currently between 10 and 11 dB). The router settings allow a change in the target SNR and since making a change to that 13 days ago it has never dropped below 10.
Before changing my settings, I saw it as high as 15 and as low as 4. I thought that it was DLM making the changes but accept that I'm wrong
Using a Fritz!Box 7530