@mijostyn : It’s inconsequential.
" Professor Erik Löfgren [6] of the Royal Institute of Technology in Stockholm, Sweden, and is the earliest work known to the author which gives an analytical treatment of tracking distortion and develops a new optimum alignment method to minimise it. Löfgren provided mathematical equations to the distortion model developed by Olney, and undertook a Fourier analysis on them. The results confirm the relationship postulated by Olney, which translates into the distortion being proportional to the tracking error and inversely proportional to the groove radius. The tracking error divided by the radius has become known as the Weighted Tracking Error (WTE). Löfgren then sought to minimise the tracking distortion by minimising the WTE. Löfgren developed an optimisation method which involved applying the minimax principle (as used by Wilson) to the WTE. The maximum level of the distortion is then represented by the slope of the tracking error graph rather than by the level of the tracking error. This method results in less tracking error at the inner grooves where the wavelengths are shorter. The introduction of this inverse radius weighting complicates the analytical solution, and Löfgren uses an approximation method which relies on the error angle being small. This is a reasonable mathematical approach, and incurs very little error. An interesting feature of the optimisation method is that the null radii will later be shown to be the same as those provided by the later authors. The optimum solution from Löfgren provides for an offset angle and overhang which minimises and equalises the three resulting WTE peaks across the record playing surface. This three-point, equal-WTE solution has continued to be applied to the present day, and I refer to this as the ’Löfgren A’ solution.
"An objection that could be raised against the [Löfgren A] calculations is that the three maximum values of the parameter δ/r (ie, WTE) are not of the same importance. A greater importance should actually be attached to the maximum at r* than to the maxima at the inner and outer recorded radii r1 and r2, first because δ/r changes only slowly in the vicinity of r*, while in contrast δ/r changes very rapidly at r1 and r2. Secondly, the inner and outer radii r1 and r2 are not necessarily utilised with each record. Because of this consideration one should permit somewhat larger values of δ/r at r1 and r2 than at r*.". Clearly, Löfgren was concerned with the extended period of slowly-changing distortion between the null radii. Thus, the central WTE (and distortion) peak should be lowered, while allowing for short periods of higher WTE (and distortion) at the inner and outer groove radii. "
In any standard calculator you can read these:
Maximum error always be: Löfgren B , Maximum distortion always be Löfgren B and Average RMS Distortion always be Löfgren A by around 0.04% that has no consequence in what you listen.
You know that there is nothing perfect and only trade-off choices. You prefer B no problem.
R.
