Per Ticket Fees and Flex Packages

We have an artist who has a required $1 per ticket artist charity donation which we have always set up as a fee (we assume this is standard practice).  However, this artist is also being sold as part of our flex package (5 or more performances) and we cannot seem to figure out how to get it so that it operates correctly.

The ideal is that there is a $1 per ticket fee applied to the order for each ticket issued to this performance only, regardless of whether or not the performance is in a package or on its own.  Current set-up is Performance Seat Level with only this performance selected (all relevant price types and MOSes select as well of course).

We tried including the relevant flex package, but that did not seem to apply the fee even when this performance was included in the flex package.  We tried to create another fee that worked on the package seat level and were able to work out ways where it assigned a $1 fee for each package seat regardless of whether or not this performance was chosen as part of the flex package as well as another way where we generated the $1 fee only when that performance was part of the flex package but then Tessitura apparently decides that the fee should be applied to every ticket in the flex package and not just the one relevant performance.  We assume the problem arises due to the fact that the concept of a "package seat" is different for a flex package than for a fixed package, but that does not help us much.  Order-level and constituent-level fees are out for obvious reasons and we were rather hoping to not have to make this a user-defined fee.

The best idea we have so far is allowing the package to have a minimum of four in Tessitura while we continue to tell our patrons "minimum of five" and just pull this performance as an additional single line item rather than as part of the flex package, but we were hoping there was a better option out there.

Any ideas?