Archery question - again? (in General)

I recently untrained archery to test if I really need it. Based on my current setup, I fight teams which have lower dexterity than mine. I have low dexterity on my tank aided by EC casted by my other 2 minions. My tank is using a mageseeker bow (it has a +50 on it) without archery trained. I looked at my fightlogs and I can get 2 shoots per round on most ocassions in ranged and damages decreases significantly in melee.

My question is, Why am I gettting doubles instead of singles when I'm supposed to be penalised by 80% for the lack of archery? Is this a bug?

Based of my calculations (not too sure about the numbers), max dexterity chance to hit is +150 and my mageseeker bow is +50 so that adds up to a total of +200. 20% of that is only 40% chance to hit, so why am I getting doubles instead? Is there something wrong with my calculations?

I think you start off with 20% CTH, and then other factors add on afterwards, but I'm not sure.

Per the exact Archery changelog:

Archery is different: it no longer affects being able to fire during round 2 of ranged combat. Instead, it affects the ability to use a bow during all rounds -- without archery you will have about 20% of the chance-to-hit that you would have with maxed-out archery. Interpolation between these extremes is linear. (That is, 20% of both DX and non-DX based chance.)

Max dex chance to hit is 160%.

I have noticed the same things you have and cannot really explain it.