I think making an arbitrary cutoff of a mature hairline is silly. The gray area between NW2 and 3 is confusing enough as it is. A mature hairline can be anything from a Norwood 1.5 to 2.5, imo. It all depends on if the hairloss will stop there or not. It all depends on which follicles are DHT resistant and which ones arent. There are other theories such as testosterone itself is what makes the temples recede, while DHT is the enemy of the rest of the hair on the scalp. I honestly dont know. All I know is that there are men out there, who progress to Norwood 2.5 and stop. I am not saying this guy is one of those guys, just that its possible.
A good indicator is if the hair that you have is thick, or if it is thinning. If your temples have receded but you have no thinning then I think you are good in most cases.
Now whether you consider Norwood 2/3 serious/considerable/noticeable hairloss is different for each person. I only would consider a hairline like that serious hair loss if it was accompanied by noticeable thinning. That is just me though.
A good indicator is if the hair that you have is thick, or if it is thinning. If your temples have receded but you have no thinning then I think you are good in most cases.
Now whether you consider Norwood 2/3 serious/considerable/noticeable hairloss is different for each person. I only would consider a hairline like that serious hair loss if it was accompanied by noticeable thinning. That is just me though.