Ann: On Market Share Buy-Back, page-125

I'm not sure where you got that idea from, but the announcement clearly says their motivation; they consider the current SP to be too low, so they are doing SBB to raise it. Its not to buy on the dips or provide support as you suggest. They explicitly want a SP higher (in fact if you look at SBBs by banks etc, they rarely say so blatantly that the SBB is the raise the price).

Your comment about long period of time is correct, they have 12 months. But presumably if this is the lowest SP we will see in the next 12 months (due to their own buying) I would expect TC to take advantage as much as the rules allow.

I agree 15-20c in short term. If they improved communication I would say 20-30c is not unreasonable.

But as for SP games, I expect they will likely increase. Once DT know something like this is on, why wouldn't they come and play the pips all day long.