Do what you want Adrian-but it comes down to this, do you consider the Sanex WTA finals an "exhibition"? That's the equivalent of what you are doing. By definition exibitions usually don't count towards rankings. The Colgate Finals did, and was the ancestor of today's WTA finals.
Sorry to be picky, but I remember these years and matches, and while you can do as you like I don't want others to be misled. Blindly trusting some fan website from a fan who probably doesn't remember from the 70's, but rather from the 90's, can have it's drawbacks.
I hope you recall this Adrian if 20 years from now someone dimisses Martina Hingis' two tour ending title wins as "exhibitions"
merely because they have no memory of them and 3 matches looks skimpy on paper. Memories have a way of getting short.
Unlike 2002, when Martina won that title it was arguably the 3rd
biggest, after Wimbledon and the US Open. Hardly an exhibition.
She deserves better recognition than that
If you don't believe me check an independent source- a good tennis magazine or newspaper from early 1980.