[VickyA]

I think the main question is whether this could be a tubular or an underdeveloped breast issue.

The description you've given highlights several traits that are often associated with tubular breasts:

•  Narrow base and elongated shape: Tubular breasts often have a limited base diameter, leading to a long, narrow appearance when   leaning forward.
  
•  Low nipple placement: Nipples positioned very low on the breast mound are a key sign.
  
•  Tissue concentrated toward the sides/armpit: This may suggest insufficient glandular development in the central front area.
  
•  Lack of upper pole volume: Very little fullness at the top with sagging tissue below is common in underdeveloped breasts.
  
•  Flat appearance when lying down: Could indicate less volume or lax supporting tissue.
  

So I would say yes, this could suggest a combination of tubular and underdeveloped characteristics.