I use Neopan 400 quite a bit and dev it in Microphen (stock) or Rodinal (1:50).
For me it seems capable of lovely detail in both shadow and highlight detail is one of Neopans strengths.
Have you considered your exposure?
I meter for the area where I want detail in the shadows and then close down 2 stops, I find that with developers like Rodinal at 1:50 that if I avoid vigourous agitation say one or two slow/rolling inversions per min I get great shadow/highlight.
This is Neopan 400 in a very dark cathedral, with bright spot-lit pillars deved in Rodinal 1:50

Shadow and highlight preservation is one of the reasons to use Neopan IMHO