I don't think I have been hanging out around here long enough to know what precisely you mean, but as I am very happy with my R-07, I might as well throw something at you while we are waiting for a more qualified response.
I am pleased with the results through-out the input range (1-100), however, there seems to be a transitional spot between 59 and 60 as if the device is switching between circuits - when moving over this point it results in an audible artefact on the recording.
When set to 60 and above with the limiter ON and NO safety track engaged, the device is said to engage a hybrid limiter function that substitutes clipped material on the fly (poorly described in the documentation) - I guess this functionality could be related to the 59-60 phenomenon.
I imagine therefore that there could be a difference in self noise above and below 60 although I haven't noticed it personally.
I am recording my stuff in the 60-70 space and don't sweat the small stuff, so I have no complaints or desire to make measurements
(I should perhaps underline that this is NOTHING like the Zoom H1 which engages digital attenuation below 34(?) and introduces a significant amount of noise.)