Thank you Richard, I would not be were I am today without your assistance and from many others on this forum, and great questions like Zach's here are invaluable to me. Thank you for helping me learn this software, I still have a lot left to learn.
I agree with Richards comments below (at least I think they are below).
Zach please 'branch' this discussion on Joe's first comment, and title it something like "Joe Mako Discusses Table Calculations" so we can find this again more easily.
Or Joe you could start a discussion titled something like: "Table Calculations: toward better documentation." Then all your discoveries (trial & error) and understandings could be collected in one place. As well as Richard's et. al.
PS: Personally, I try to avoid table calculations whenever possible because getting them to work like I want them to, takes far too much trial and error. I wish it weren't so. (And I want to repeat Joe's clarification: I love this software, and want to do anything I can do to help.)
Thank you Shawn. I believe that with awareness of all these factors the trial and error is greatly lessened, it becomes a progression. I feel sad that you avoid them, I use them all the time. I know Tableau is trying to solve this issue of complexity, but version 7 feels like two steps backwards in regards to the complexity of table calcs, so I am looking forward to them taking steps forward, even it it means removing capability in order to achieve simplicity and usability. Table calcs in version 7 are broken in my opinion, so I have a long list of evolving workarounds and exception handling.