I'll try to explain again, Andy:
Being penalized for international market imports makes sense: it's money leaving your economy. Buying local/common represents value-added activity that benefits your country/enterprise or your direct partners. Great.
Exporting products to the international market, however, represents you GAINING value from people outside your economy. It's the holy grail of any economic system: bring in more money from outside the system, thus becoming wealthier. (In economics, recall, cash flows the opposite direction of goods.)
But in your scoring system you're penalized (negative points) both for buying from the international market (OK), and selling to the international market (NOT OK).
Experienced playing should be: buy local, sell global. Pay yourself to make the things, then get paid by everyone else for making the things as well.
Doing this 100% is impossible if everyone is playing at the same level, because your customers are ALSO looking to buy local.
For this reason, I think it's also sensible to score based off of SC$ value of import/export rather than satiation % as you seem to do: What matters is which way the wealth is flowing (at least for an Enterprise, for countries the objectives should likely focus on the maximization of societal welfare).
Your scoring system suggests that any international trade at all is bad, even if its obviously to the economic benefit of the given entity.