Hi Jan,
Workfront is certainly capable of capturing the information you're tracking in Excel as custom data, and I'd encourage you to pursue that idea, since -- by having it in Workfront -- you can then get more value out of the data than you could as an attached Excel document, such as reporting on it, editing it inline, and charting it. The trick is deciding WHERE to put that custom data. Using a Goldilocks and the Three Bears analogy, here's my take:
Project Level (TOO HOT): with 6 custom fields and 100 orders, you could create 600 custom fields at the Project level...but that would be very cumbersome to enter, exceed the 500 parm per form limit, and be extremely rigid and unmaintanable.
Issue Level (TOO COLD): you could raise 100 Issues behind each Project, storing the 6 fields on each Issue independently. Not a bad solution (in fact, I've used this approach), but since three of your six fields are dates, my bet is that there'd be advantages to show them on a timeline, so
Task Level (JUST RIGHT): if you use the Task Planned Start Date as the Ship Date (assuming that's "first"), the Live Date (assuming that's "last") as the Task Planned End Date, and the other 4 fields as Custom Form information (including the "Date to IS" as something that MUST be filled in by a certain point between the two), you can then visualize the acitivity of the first two dates over time using the Task Gantt view, and the presence (filled in) or absence (white/red if "too late") of the latter date in grid format. And edit all of the above in a Task grid view. And (if it makes sense) create a template of these 100 deliverables, so that Projects are created with all these Task "pre-loaded" for the orders. Or (if it doesn't make sense), create a template with one such Task in it (or several related Tasks in it), which can then be easily Inserted into the Project as needed.
Hopefully this gives you some ideas. If you're currently working with a field support consultant from Workfront, they (knowing your business) will be in a far better position than am I to advise you, so I'd encourage you to ask them to help you make the best choice.
Regards,
Doug