I have never said the exact same model of airplane could not fly at a higher weight in a different country and the same model be a LSA here in the USA. What I said was that an airplane can not be certified at a higher weight any where and still be a LSA.
I think you are misunderstanding the meaning of certified. An airplane is certified when it is issued a airworthiness certificate. This is done on a individual airplane basis. What the airworthiness certificate is certifying is different based on what type of airworthiness certificate is issued. This is why any airplane since its original certification can not be a LSA if it had a gross weight higher than 1320lb for a land plane. The fact that other airplanes of the same model have been certified at a higher gross weight means nothing when it comes to certification of a LSA aircraft other than to show design strength.
If by "an airplane can not be certified at a higher weight any where and still be a LSA" you mean an individual airframe, then we agree. The confusion I was trying to clear up is the use of "airplane" to mean an individual airplane, but it's also used to mean a type of airplane. Just making sure we're clear on terms.
I understand certification. Experimental Amateur Built (EAB) airplanes have an airworthiness certificate, but no certification (unless you count the DAR as 'certifying' that the airplane meets general safe build practices). Factory built airplanes are certified under Part 23 standards, S-LSA & E-LSA are certified under ASTM consensus standards.