"Or am I off-base on this?"

Well...yeah probably. Where I work, the company is typically the one that does the announcing. Otherwise, we would all be doing exactly what suits us without regard to how it affects one another. You can announce your new plan all you want, but be ready for your company to tell you what they think about it.

When in doubt, I think that a proposal goes a lot farther than an announcement when it is coming from an employee.

As far as compensating you for the conditions of your commute...dude, get a grip. I could see them allowing you to telecommute on the few bad weather days if you had proposed it rather than announced it. But if they say no thanks, I can't see you being entitled to any additional compensation because of the manner in which you chose to get to work.