Difference between a 'mature hairline' and early MPB?

[jackroylance]

Second post on here, the first had pictures of my hairline with me unsure what to define it as and worried for those dreaded early symptoms that I will be destined to lose it!

Most if not all of the feedback I got was that I just had this phenomenom of a mature hairline, Norwood 1.5 (2 at the worst) and no other signs of losing, especially with quite a strong family history of hair.

However, after looking at other people's posts and blogs I was a bit confused as to the difference between a mature hairline and an actual receding hairline? I've seen some photos of hair I thought was struggling and see people say is fine and also some hairlines I thought were good but appear to be receding?!

What is the actual difference?!