You only got paid for touching trips on the primary and secondary vacation. Some of what's being posted is a bit of a myth. Trips were generally 3 days long back then. As we graduated to longer and longer trips they capped the trips touching pay to a limited number of days outside the actual vacation footprint.
It was a very senior oriented system. As a junior bidder it was quite possible to get a line where no trip fell within your vacation or touched it and the vacation week became valueless.
You're also correct on the bidding. The summer weeks were gone in round one.
Our current system is fine and more fair across the seniority range. We just need more value per week and for vacation to be pay and credit.