My Router Download/Upload Speed Sync At Fixed Speed

Hi,

I restarted my router three times and still getting exact same speed Down 39997/ Up 1999

My line Downstream/ Upstream noise safety coefficient (dB): 19.2/ 27.7 which are high due to speed restrictions but why i am not connecting at full speed Down 40000/ Up 2000,  why its just fixed to 39997/1999?

Thanks