I think the issues with the KM stand capacity versus empty seats is 2 fold. 1 is a number of people double up in the ultras section meaning seats go free elsewhere.
2 is the free kids STs. They are free anyway and the club could just let people rock up with their kids on match day, if going. I’m not convinced these are always used by parents. Different in the main stand where demand is fine & it’s allocated seating.