Coverage of journals: date or volume format

We were reviewing the link resolver by Serial Solutions. What struck me was that they only described coverage of subscriptions in terms of date format.

To my fellow librarians: how do you describe the coverage of journals in your system. In date (start and end year) or volume and issue format.

In my opinion to describe your coverage best you should use six repeated fields.

1. Start year
2. End year
3. Start volume
4. Start issue
5. End Volume
6. End Issue

These should be repeated to account for missing years or volumes.