Thanks for your patience, Harry -- choir practice was good (and called for). Alright! Back to your calculated date question, and my as-promised Many Thoughts:
The "https://community.workfront.com/discussions/community-home/digestviewer/viewthread?MessageKey=2098c762-160f-4a56-a185-d43ab59cecf7&CommunityKey=ccf3381b-a473-4ef2-9f81-4dd3244cf522&tab=digestviewer&memberkey=5n1H2oNYJSCtYvFfR1xT4UEFt7nqrC17yB0zotcNSvrbyKEPM8zot9rvNuJwAvOy23KP3d2HROo%3D#bm2098c762-160f-4a56-a185-d43ab59cecf7">Tip Jar Topic: "Guess" or "Know" the Right Project Start Date? thread discusses a similar topic, whereby -- given a known, desired end date -- a formula can be used to reverse engineer the optimal (e.g. giddy up) start date by deducting a known interval of time.
Given your use of "In Market Date", you could adapt the same concept but make the formula a Little Smarter so it takes into account the appropriate lead time depending on the Media Type selected.
For example, you could create a Custom Date Parameter called Ideal Start Date, with a formula such as this: IF(Media Type = 'TV',"https://support.workfront.com/hc/en-us/articles/217196767-Understanding-Calculated-Data-Expressions">ADDDAYS (In Market Date,-90),IF(Media Type = 'Radio',"https://support.workfront.com/hc/en-us/articles/217196767-Understanding-Calculated-Data-Expressions">ADDDAYS (In Market Date,-60),...))
Once you have these (very important) dates defined at the Project Level, you can leverage them in Workfront Reports for Filtering, Sorting, Grouping, and comparing (e.g. color any Task that should be done 30 days after the Ideal Start Date but isn't yet in red)
If you're interested in other kinds of powerful date based visualizations, I also invite you to consider our "http://store.atappstore.com/product/ubergantt/">UberGantt and "http://store.atappstore.com/product/pdfcalendar/">PDF Calendar solutions (among "http://store.atappstore.com/products/all/">many others )
Regards, Doug Doug Den Hoed - AtAppStore Got Skills? Lend a hand! https://community.workfront.com/participate/unanswered-threads