The rate that Kkma quoted is for 2 adults and one child.
Because one of you is on a means-tested payment, the total income that you receive cannot be greater than the maximum payment of that means-tested scheme for your family size.
The rate for 2 adults and 2 children is €372.40
If you were both on a means-tested payment, this rate would be divided evenly in two. Because you are on a benefit payment, you receive the full personal rate (€188) plus half-rate for the 2 children. Your wife's personal rate is reduced accordingly and she receives the half-rate for the 2 children as well.