Timelines are often an exasperating subject for companies.  For public companies there is always the seemingly never ending pressure by shareholders for some sort of timeline and subsequent update to its advertised end result.
   So do you put something out there that fits, to the best of your knowledge, a projected future end date? If you do. you will no doubt  be subjected to increasing pressure to maintain that timeline from the selfsame folks who demanded it in the first place.
    Timelines regardless of industry practically beg to be broken. Mining is one example. The construction of a mine is open to so many variables that they almost never meet their advertised initial timeline, or their next two or three for that matter.Government procurement timelines are laughable. Example: Cobra Helos or F35's to mention a couple. Government shipbuilding programs are also, "fall of your chair laughing" disasters. As far as timelines are concerned private companies seem to treat government contracts as personal piggy banks.
 By the way, ask Bombardier for the timeline on their latest aircraft.   In the construction industry, large edifices financed by the taxpayer, (read government), such as sports stadiums, bridges, hockey arenas, convention centers never come close to their much ballyhooed timelines, never mind their cost over runs. 
One industry that always meets its' yearly timeline is the motor vehicle industry. New models roll out on time every year.  Can you think of another industry that could survive the number of recalls that happens in this paticular industry. I mentioned  shipbuilding; one country that does manage to produce ships mostly on time is South Korea, there is one caveat though. A fair segment of the seafaring types won't sail on an SK built ship that is more than ten years old. The steel quality is poor and poor construction can only stand a certain amount of battering from the worlds oceans. To do a job right takes time, patience and quality material.

Timelines should be looked on as guidlines that are subject to change. I agree that they should be updated whenever possible, the timeframe between updates could possibly be determined by the complexity of the item being produced and the number of sub-contractors or suppliers you have to deal with plus your own and other management teams.
In our case, for me, a six month leeway is acceptable before an update should be provided. (Maybe I'm being generous, maybe not). It always seems that everyone in the foodchain toward the end product can find someone else to blame.
     The Pharmaceutical industry causes me to sometimes shake my head. How can they produce so many products that are accepted by the FDA, HC and the various European Health administrations with the ridiculous amount of contraindications attached to them.Some examples:Xarelto, Linzess, Otezla, Humira, Lyrica, Neulasta, Victoza, Cosentyx, Entresto, Tresiba, Anoro, Celebrex is one of my favourites. During an episode of bad back pain my GP hauled open his sample drawer and gave me some to try. I took them home and checked them out on my PC. Result was I didn't take them. The next time I saw my GP I pointed out that one of the side effects was death. He laughed and said that would certainly fix my bad back.
Perhaps if you are a multi billion dollar industry regulating bodies will cut you some slack. It is just not the same for small companies like TLT, if you don't get it right you are toast.
  I realize that this may produce a few rebuttals and that is good.