A Magento product is created with the SKU in the format of DISC[release id]N[x]

For example DISC17518N1 is the sku for 'Jeff Mills – Waveform Transmission Vol. 1' -  https://www.discogs.com/release/17518

If you have 10 listed that are exactly the same the system will add a qty of 10 to this product

For each new variation of price, condition, comments, location etc a new product is created with the suffix adjusted so DISC17518N2, DISC17518N3 and so on.

So for example, you might have
DISC17518N1  VG+/VG+  3.99
DISC17518N2  VG+/VG+  3.49
DISC17518N3  M/NM  10.99
DISC17518N4  M/NM  9.99  'Sticker on cover'

 

Discogs inventory is imported into D2MPro > Discogs Imports > Inventory

Listings are allocated to an SKU. 

 

Discogs Inventory Grid