Thanks again. I have a few more questions (also ask for my friends):
i. Concerning the valid date of 'the approval of the waiver': Is it the date on which the (favorable) recommendation letter was sent by DOS or received by oneself/international office?
ii. Quite a few friends of mine extended J1 before got the recommendation letters from the DOS which only cover the previous J1 periods. Does this also mean they have owned the 'second' J1 status?