IA you are not correct. First of all EASA TRTO's went out many years ago replaced by ATO.
It is not mandatory with most states I am aware of to go through an ATO as there is no training requirement so long as you meet the requirements from Commision Reg 1178 just a Skill Test and evidence of flight hours on third country license.
Next you do not lose a 320 rating after 2 years. You can not fly the plane for years and keep it current by LPC every year with no ATO. Or let it lapse with increasing "recommended" sim sessions as per ATO discretion up to 3 years as safelife says.
I'm not trying to pick an argument but if you're not interested don't make false statements if you don't know, it misleads.