Ward got $5 and $6.5 million for the first and second fight, respectively.
Kovalev got $2 million and a percentage of the profits for the first fight, and in the second fight opted out of a guarantee in exchange for a percentage of the PPV and live gate.
In other words, no, neither of them got $20 million for either fight.
Edit: Just looking at the revenue generated by the rematch, and your figures are way off:
$60-70 PPV
100,000 buys
$7,000,000 PPV Revenue
-50% (Cable Company) = $3,500,000 PPV Revenue
$2,200,000 Live Gate - 25% (Venue Tax, AC, etc.) = $1,650,000
$5,150,000 TOTAL REVENUE
They actually lost money.