Can't say that it has ever mattered. Why can't you go without the IR or, at the least, what does it matter if it expires shortly after your departure?
Any new operator has always wanted to do a base check/IR anyway prior to line training. This is absolutely the case, surely, in the situation where a new type rating is called for?
The problem arises perhaps when you want to leave one operator without going immediately to another. Then your IR might expire and you might face an interview without being current. That can put a somewhat different complexion on the thing. But on the whole, since any new operator is going to require you to be checked out, don't think it makes a lot of difference.
