when is the first payment? do they choose or do you?
If you were to order today, and decided to use the FLEXPAY option (that's how I have had all of my SSC figures so far, it breaks the payments up quite well, into much more manageable chunks), it would open a small section of options in a grey box, that looks like this...
It will have the drop-down menu selection for day of the month you want to pay, and one for the number of payments you might want to make. These vary from figure to figure, Cap:A was 4 as was Hawkeye whereas Loki and BW are 3.
This also shows you that if you did purchase today via Flex, the first payment they would expect off you would be March on the day you have selected from the previously mention drop-down menu.
I ordered at 11.10pm on the 14th June 2012, made my first payment on 25th Oct, as can be seen from my account page...
Sadly, because of HT delays, it looks like I wont be seeing my BW figure until next month. That's the only thing with Flex, SSC wont take your last payment until they have stock in hand to ship out.
I hope this helps. Sorry for the delay in responding.