Another reason not to give an advance accurate time frame is it gives our enemies (BP, bashers, etc.) information they can use against the company and us.
I am still upset with them last year giving all the details of their contacts with Mexico too early. You want to bet that someone called up their friends in Mexico and told them to slow it down to a standstill? They should have mentioned as little details as required to be disclosed and no more, and then when a deal is in place, announce. More like they are doing in Brazil right now. Vague references, and an announcement only after the deal is in place. These institutions and companies are not going to back out after signing contracts. But before they are subject to interference.
Let them guess when these are to be filed. Harder for your enemies to interfere with when they don't know the timing.