EgoSlayer, on 14 March 2013 - 06:23 PM, said:
too heavy means your mech would exceed its weight limit. Limit reached means that location can't support any more armor.
Confirming that this is correct.
The messages are clear as they are.
Too Heavy = You are not yet at the location's armor limit, but adding one more point would put you over the 'Mech weight limit. In this instance, you can add more armor if you lighten the 'Mech up by removing something.
Limit Reached = You still have weight to spare, but you have reached the maximum amount of armor that the location can carry. In this instance, you cannot add more armor to this location no matter what you do.