That's actually correct, but I can see why it is unclear. Basically, when you look at Armor rows and Anti-Armor columns, you see all blanks because the armor never wins against the anti-armors. But, when you look at the anti-armor rows and armor columns, you see the data for all of them (at the same mark level).
Here is how data is shown:
1. The engagement lasted more than 500 seconds without being resolved (it shows >500s for both attackers).
2. The attacker (ship on the row) won: it shows the time and health percent remaining.
3. The attacker (ship on the row) lost: it shows nothing in the cell.
4. The ships did not fight at all: it shows nothing in the cell.
The original intent was to make it very easy to see where ships were strong, with having no extra clutter in those cells for case 3 above. But, I'm open to shifting that if people think it would be more clear...