I doubt Mayweather's decision to drop a belt has anything to do with any other fighter. Most likely the reason for dropping the belt has to do with sanctioning fees. Any sanctioning body should have fixed fees and never a percentage. If the WBC is using percentages to figure the sanctioning fee, then I can certainly understand why Mayweather would drop the belt.

3% of $1,000 = $30.00
3% of $1,000,000 = $30,000
3% of 22,000,000 = $660,000