Crazy Kanga, yes, average days, and your EMH plan sounds good.
Would it help if I associated the words "Slow," "Average" and "Busy" with each rating on the chart? A day rated 1 through 4 would be slow, 5 through 8 would be average, and 9 and 10 would be busy. Would that help?
disneyfett, I agree having an average of 6.5 on the scale isn't as intuitive as a 5. We tried to balance a couple of competing factors with the numbering system. One was that the scale had to be easy to remember. Because of that, we felt it had to be linear. (The old scale was certainly not linear, and even I had trouble remembering the wait times associated with each number.)
Since we'd used a 1-10 scale in the past, we also thought we should use a 1-10 scale going forward. Finally, Disney posts wait times in 5-minute increments. All of these things effectively restrict our choices for the time quantum to 10 or 15 minute intervals.
Since most wait times fall between 45 and 85 minutes, we thought the 10 minute increment was a better choice. Also, I think most people don't really differentiate between waits of more than 100 minutes - they're all bad - so the upper end of a 15-minute scale would have been largely irrelevant to most people.