That doesn't sound right at all. You would want to lay off the bottom performers, it isn't a lottery. Imagine if a company said 'we need to get rid of 20% of our labor cost' and just ran a random number generator and got rid of the people who's number came up.
No, you want to get rid of just enough of the top performers to significantly lower labor cost while keeping enough that they feel safe. You can shed as many of the bottom performers as you like without worry. Gotta make those top performers do 2x the work for one paycheck.
