As I cannot PM submitter (his mailbox is full), let me explain here the edits.
First, we have a radio drama to introduce Iczelion story arc. Iczer 1 and Iczer 3 characters are also part of the cast.
3 CDs are released to cover the full story and a
soundtrack soon afterwards. Nothing unusual here.
Later, an OVA project is started. They changed quite a lot of story plot, remove Iczer 1 and Iczer 3 and go idol nonsense with 3 other Iczelion (Black, Gold and Silver).
The reason is quite unknown but they kept all of the drama BGM for the OVA OST; maybe not enough money, Kawai or Yano too busy, etc....
So this is quite uncommon but this OVA OST and the drama OST have almost the same material in common.
There would be only one CD, I'd agree with "Category: Animation, Radio/Drama" and OVA as "Products represented" but there are 2 CDs so I keep the split as it is commonly used/advertised over the net.