(You need this because your original parsing of OrderDate on top of your Load statements will not affect the following lines, they will still use original OrderDate as read in from Input, not the parsed one).
Today I tried your solution again, and finally I got it to work
But now I have one 'small' problem...
Sometimes a costumer gets our products, but then stops.. after, for example, a half year, the customer starts buying our products again.
In my interval, he buys products each 10 - 15 days, but because of the half year stop, one interval is for example 184 days. This gives an incorrect avarage interval (should be 12,5, but ends up way higher), especially costumers that haven't bought so much (not so many values).
Is there a possibility to get rid of these strange values (if not in line with the rest, reject the value or change the value to an avarage value)