Hi Barry,
My point is that I believe that as long as the desired Y+ range is maintained, I end up with a higher percentage of surface cells that get layered when I use ‘Relative layering’ and this higher percentage of layered surface cells would intuitively seem to me to provide more accurate results.
The reason for this is to make sure the simulation does not end early due to an arbitrary residual value being reached. I watch my simulations as they proceed and stop them manually when the forces and moments are considered stable for a few hundred iterations. I have found that there is not necessarily a direct relationship with stable results and residuals. I find this is needed when you are trying to obtain maximum results accuracy after you have validated your setup and which actually does not waste core hours if monitored manually (this was before the days of being able to continue a simulation run 
. I have saved more core hours by watching results convergence and not having to worry about residuals stopping my run which would then require me to start a whole new run.
Those numerics were suggested by @Dylan who has been able to validate his vehicle CFD setups to AMAZING accuracies as you can see at the end of this post.
Dale