When you start ESO Plus you are charged same day, the next time you are charged is on the day of the month you're account was created (this is the day all sub's renew on Xbox).
Say you created you're account on December 18, 2006 all your subs like Xbox Live will renew on the 18th of the month.
Now you just started ESO Plus on July 30th and it is taken from your card right away.
For some reason MS is not gonna charge you're card again till September 18th (but this is payment for you're August sub not September), they skip a cycle or something.
So you will not receive you're Crowns until the payment hits your card and the proof they ask for won't show up till that time either.
So we need a solution to this ZeniMax. Give us the Crowns on the date we first started our sub, like August 30 if you were following my example. This policy is costing you more in potential subs coming back than the cost of a few digital Crowns you would "lose" I'm sure.
Found this all while chatting with MS support when I couldn't find the proof ZeniMax asked me to supply. My last transaction on Xbox.com said 8/14 but I needed to prove 9/14 but Xbox support told me that won't show until 10/04 because I haven't paid for 9/14 yet and my card will be charged 10/04.