I know the majority of you find it easier to see a spread-sheet example, but I've decided to make this 2 minute video explaining the issue instead (as I am utterly convinced there is a quick explanation to what is going on here).

It's driving me bat-crazy. Why the VLOOKUP won't work I have no idea. The data points are identical in length and the date ranges are == to each other :s!?

Please spare 2 minutes to watch this video: http://screencast.com/t/Ule7fk8g7F8v

Thank you kindly to all of you who can help in anyway shape or form!