The “number of sets” bit is silly. Come on, guys; they aren’t bus drivers being paid by the hour, they’re professional athletes whose pay is rightfully based on the market demand to see them play. Should they get paid less if the match is a 6-0, 6-1 wipeout and only takes an hour to play?
They should be paid whatever the market dictates. Since the men’s and women’s tours are separate, the pay rates should be independent of one another. Let 'em set it at whatever the economics dictate.