Ok, here goes....I'm not sure I can buy into this methodology Len. I agree w/ an earlier posting, a lot of us Dis'ers (and UG followers, TGM, etc) tend to go during the historically low volume times. So I believe we as a group, can make things look more inflated for those time periods as we'd be most apt to to register our trips on your site. I would think local hotel occupancy rates would be a much better yardstick. And even there, I think they need to be adjusted for conventioneers vs. "regular" tourists.
Holidays and wide spread school vacations are definitely imp't factors. Saying crowds would be higher the next 2 weeks vs. Memorial Day weekend, however just does not seem right.
I'm a research scientist at a Marketing Research Company (ok, I was before I became a stay at home Mom) and modeling and interpreting the data is very tough. There are always so many other factors that can affect things....
For instance, let's just look at grad nites.
Group 1: These people avoid MK those days as it closes early and they may not have hoppers and want to enjoy a full day at a park. So they opt for Thurs or Sun as a better option to visit MK and do a diff't park on Fri/Sat
Group 2: These people are raring for EMH morning on Friday!!! Thought process being hoards of other people are staying away...I'll see more from 8-2pm and be able to go back and relax pool side. If I want, I'll catch an evening show at another park. MK on a grad night is a great choice.
Group 3: Similar to above they see an oppty in doing MK on a grad night day but prefer a 9am opening over an 8am opening so they go on Sat. It won't be such a zoo since it's not open late.
Group 4: Let's do MK on Wed w/ late night EMH. Maybe get up early and do a few hours before returning for a nap...then return to the park around dinner and have a fun night. Plan to sleep in on Thursday making many of the parks a great bet for Thurs. morning.
And I'm sure there are other scenarios too and of course weather. I know you quote someone in your UG saying basically "UG says to do this....we think maybe everyone will be doing that so we will do the opposite....but then maybe others are thinking let's all do the opposite...so perhaps we should do what UG suggested afterall." I believe your response was you were flattered she felt so many people followed your advice but at this point, it is really still a very small percentage of the people who travel to WDW who read and follow the UG plans.
Again, on this site, we all tend to be avid readers and Disney-aholics so we can easily slant the data. What I'm getting at is that I think we (myself definitely included) start to place too great an importance on getting this "right". What's really important, as you have said many times, is having a good touring plan.

Realizing the crowd levels will probably be higher than expected is also imp't....tourism is up and the celebration is about to kick-off! But no, I just don't believe the last week in April is going to be approaching the crowds over Easter. I've been calling to change some PS's recently and have been able to get very good times at restaurants like Liberty Tree Tavern, Crystal Palace, Chef Mickey, Coral Seas and even O'Hana. I checked on airfare (we fly southwest) The nonstop flights we had to/from Orlando were clearly well below capacity. I was able to rebook my tickets a few wks ago and saved $60pp. For my family of 4 that was $240!!! If this was a busy travel time that would not have been possible.
So....I don't know...maybe getting to this level (predicting daily attendance levels for best days in the parks) was just a little too ambitious.

Disney is certainly doing their "best" (probably w/out even trying) to make predictions more difficult. We all had to struggle w/ making PS's at a 90day mark when calendars weren't even available. EMH schedules are still very fluid and the MYW tickets w/ hopping being an option are definitely impacting how people tour the parks.
I know you're doing your best....but imho....I think perhaps this level of detail was just a bit ambitious and I don't buy into some of the assumptions. But I still LOVE the UG!!!!!!! And all the wonderful info'n you share on this sight!!!!