Lets try an example.
Assume that in the last general election 100,000 people voted.

In Scenario A: We have only 30,000 voters that voted in this election. That means we use the formula for when less than 40% of the number of voters voting in the last general election voted this time. To meet the supermajority and validation requirements we need 60% of 40% of the number of people voting in the last election, which was100,000 people. That means 24,000 YES votes are needed to meet the supermajority and validation requirement.

In Scenario B: We have 50,000 voters that voted in this election. That means we use the formula for when more than 40% of the voters voting in the last general election voted in this election. To meet the supermajority and validation requirements we need 60% of the number of people voting in this election, which is 50,000. That means 30,000 YES votes are needed to meet the supermajority and validation requirement.