Do what you think is most appropriate for your own situation.
Not knowing any of the background history here with your school, payroll, etc., I might (suggest only) that it might still be a good thing for you to attend. Knowledge is power. Plus, it will make it look like you stepped up, whereas other teachers might not. And, you've been very fortunate to have so many wonderful vacation days this summer, that two days doesn't seem like much to forfeit to me. But again, please realize I'm not in your shoes and don't know the particular circumstances behind the request.