In Matter of Northwest Engineering Co., 863 F.2d 1313 (7th Cir 1988), the Seventh Circuit Court of Appeals was faced with a contention by employees that because their entitlement to vacation pay for the year 1982 depended upon their working at least one day in 1983, all of the vacation pay was "earned" for bankruptcy purposes on that day of vesting, within 90 days of the debtor's filing of its bankruptcy petition on April 1, 1983.