What about your 42 days annual vacation. Theoretically, if you get 4 days off consecutively in a month, couldn't you add another 4 (for example) days (vacation) to get a total of 8 days off in a row?
Some months you perhaps wouldn't even need to use the vacation leave, in order to "save" up more for days for when you need it (in regards to the bid group).
Wouldn't this work? Just a thought.