It feels like a punishment for her. But I see it being consequences for her actions. She chose to put off kids for OM. The consequence is she loses days. If her actions interfere with plans you have made. Then I can how she would owe you one. Especially if she isn't willing to return the favor. I see no issue with the arrangement. Your choosing to hamdle things like a business partnership. That is how you both agreed to coparent.
The consequence is losing the one day. It's the loss of the second day that's the issue.
And he didn't say that all these times were for the OM. He charges the extra day for conferences, for example.
Me: 44 H: 44 Kids: 20, 16, 16, and 10 Together/Married: 22 years H announced he was emotionally detached and considering D: 4/4/16 H announced he is going to try to stay and reconnect: 5/1/16