Error? different definitions for registration 'fitness' in source code and documentation

I noticed an inconsistency of the definition of “fitness” between the source code and documentation. Both Python and C++ documentation state that the number of points in the target is the denominator, yet the source code clearly divides by the number of points in the source.

I saw that this was brought up by another user over a year ago as a GitHub issue #1459 (intel-isl/Open3D/issues/1459). Qianyi Zhou (@qianyizh) replied “we should go with implementation”, but I am reposting the question here as requested by @germanros since this inconsistency still exists. I have provided updated links below