John_T,
I just typed a reply to your questions, the length of which rivaled my last post. I took too long, and my sign-in timed out! Danny, we need more time!!!
Gotta hit the sack for an early morning aviation commitment, but in brief - the 60M additive to TORA (Provided that 60M or more of Clearway is available) is accounting for the airborne portion of the Takeoff from Vloff to V2, and the 50% requirement above the runway. And Yes, it is with the manufacturer's and CASA's approval upon official provision of the 'worst case' distance for this manoeuvre.
I just hope that I can remember all the other things that I said for when I get back and can answer you properly. In the mean-time, the mention of the 50% rule should arouse a few JAR-25'ers
To your first question, no, we were competitors in a previous life, a tongue in cheek reference to the generic XXXX airlines of your moderatorial insertion a few posts ago.
Regards,
Old Smokey