I am in the process of making a high AC fighter....
it seems to me that the class ability should read:
At 3rd level, a tower shield specialist gains armor training as normal, but while he employs a tower shield, the armor penalty for the tower shield is reduced by 3 and maximum Dexterity allowed by the tower shield increases by 2. This benefit increases every four levels thereafter as per standard armor training.
This way the armor training increasing by normal... but allows for the realistic use of the Tower Shield
