Map Update Time Delay

I replaced my 130s with a 140s for a net cost of $40, cheaper than
updating maps. I downloaded and installed the free 3 month map update
offer. I moved from Framingham, MA to Burlington, NC a couple of weeks
ago. The unit got me from there to here flawlessly, lane guidance worked
(not sure how useful that feature is). It seems to have a little problem
withing the community in which I'm living, but I'll forgive it for that.
The other day I needed to go to a location via a US interstate. The unit
got it wrong, told me to stay in left lane, entrance to interstate was
on usual right hand side. Then it got confused once I was entering the
highway, at one point telling me to turn around. Later, I asked around
and apparently they had reworked that part of the roadway within the
last 6 months, so the instructions were correct for the old way things
were, but now I'm curious, how long before a highway change makes it to
the database. Street Atlas 2010 also doesn't seem to be updated
As a matter of interest, the local BankofAmerica branch was relocated
due to construction, not sure how long ago, but that hasn't made into
Google, never mind TT.