They confirmed to me price to upgrade will remain the same .
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Greetings from Thailand Privilege Card Member Contact Center.
According to clause 5.3 "Upgrade, Fee, and Validity" of your application form, during the 5-year validity term, your membership may be upgraded. If you pay THB 500,000 for Elite Easy Access, you will be charged THB 500,000 to upgrade your membership. If you pay THB 600,000 for this package, you will be charged THB 400,000 to upgrade your membership to Elite Superiority Extension.
You are eligible for an upgrade under this condition until three months before your membership expires, except for an upgrade to a new package with new benefits, which we will launch next month. '