This will show the last record for each customer first.
Click on the Advanced tab of the filter definition.
Hope this helps,
With respect to the date problem - that seems odd. However I think the only way to provide any useful assistance would be to suggest there is something strange about the model (or the model file) andask if you can make that available together with a sample of the data source so that one or more of use could assess what is happening.
How are you defining the location of the dates fields? Just Line and the horizontal position on the line? Or are you using a prefix text string as well?