yes, you need another rule to charge 20.00 for everyone else:
Total Number of Items >0;
AND SubTotal of Items >= $100.00
AND If Session Variable Exists: eCartCheckoutForm_shipping_country
OR Based on session variable value: eCartCheckoutForm_shipping_country != CA
OR Based on session variable value: eCartCheckoutForm_shipping_country != US
The calculation is Flat Rate = $20