[NOT A BUG] Damage Calculation

[FeiLing]

Pic1:

First of all: This looks so wrong. Okay okay, the Cannon being on a farmed hill might have slipped your vision.
However it doesn't matter, as a Cannon does not get defensive terrain bonuses, so it is no stronger than it
would be on flat land. Just the Shock promotions of my unit doesn't have an effect in that battle.
Nevertheless I would expect a Knight without any promotion to do better versus a Cannon on flat
land (or hill - as it doesn't matter). Guess Cannons are just kinda strong... even on defense .

Fact that does not matter here: Estimated was dealing 7 dmg and taking 4.
In fact I dealt 5 dmg and also took 5 dmg... seriously?

Now to the real problem:
The Knight has a combat strength (after all bonuses) of 21.6 vs the 13 of the Cannon.
This makes the game estimate 7 dmg to be dealt and 4 dmg to be taken.

In the picture below there is a Longswordman of mine with the battle estimation popup against the very same Cannon
(ignore that the unit is far away and wouldn't actually be able to reach the enemy unit, it doesn't matter for the calculation).

Pic2:

As you can see, the Longswordman also has a final combat strength of 21.6, just exactly the same as the Knight.
However the Longswordman is estimated to deal 8 dmg while the Knight in the same battle against the same
unit with the same combat strength is estimated to only deal 7 dmg.

Don't read this:

Spoiler :

I played this game to get the Zeupiter achievement (thus the enemies are 1x Rome, 2x Greece and 2x Egypt,
as I thought they might be most likely to build it (and 5x Egypt probably would have been too confusing).
Guess who built it? The Alexander in traditional colors (white/blue) to the very opposite site of the continent...

edit) I think I got it... as the Knight is damaged a bit, he deals less damage. So no bug here.
Maybe damage reduction due to not being at full health should be part of the combat calculation (just like promotions or the GG-bonus is).