Brad,
This may be the type of circumstances they talk about in the comment to SR 1-1a (which doesn't belong there). The basic idea is things change because people come up with new and creatiive ways to make money: condo, timeshares, etc. It stretches the capacity of antiquated terminology (rooted in William the Conqueror paying off his buddies with land to tax for the duratin of their lives) to explain who owns what, for how long and subject to what conditions.
The key difference between JT and TIC is who owns the fee. In most states, the joint tenancy owns the property not the joint tenants, that is why it does not affect marketability, financing or value - except for the interim period while the surviving tenant has to assmble papers to prove transferrable title. In TIC, each tenant is a partial owner. This creates sub-properties. Unlike JTs who have to agree to sell, TIC's can normally sell their partial interest without the consent of the other tenants.
These deals are starting to sound like a bit of a hybrid, effectively "partnerships" or maybe they are just stretching the bounds of TIC. I have read enough in Cynthia's article to believe these arrangements affect marketability and value. The details of the internal contractual arrangements have to be analyzed to be sure you are not comparing apples to oranges.
