I would like to clarify this.
Since this is an online course, granting access "forever" is not possible
The 180 days limit is a way to say: we grant access at least for 180 days, but until we are alive we will always give you access to the course material online (to the version you bought).
The student of the Online version will have the possibility to buy the Offline (on DVD) version at a symbolic price.
Thanks for the clarification.