[mike]

> some way cross-apply the license purchase price to a subscription

They did do this. From the footnote to to their original announcement[1]

Recent purchases of the Mac app will unlock up to 12 months of free use, and purchases of the iOS app will unlock up to 6 months of free use. Your individual free-use duration is calculated from your actual purchase date, respectively, and if you bought Ulysses on both platforms, we will add together both periods.

[1] https://ulyssesapp.com/blog/2017/08/ulysses-switches-to-subs...