The following is my interpretation of the rules, not a statement of truth.

1. The rules say that the first international flight and all preceding flights (let's call them first flights) must be dated. I take this to mean that first flights must be taken within a year of date of original issue. I further take this rule to be firm.
   
2. There is a another rule, applicable to TC2/TC3, that says that you can make unlimited date/carrier changes to first flights without reissue.

So, the question is: can one push the date of first flights beyond that set at original issue, using rule 2 above?

My answer is that you can, but not if it means going beyond one year of date of original issue.