You can not cure this problem by giving the HOEPA disclosure after the fact. The HOEPA disclosure is a material disclosure therefore failing to give it makes your material disclosures inaccurate.
By refunding to bring the loan below HOEPA disclosures would now make your material disclosures overstated. (Look at 226.23(g))
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The opinions expressed are mine and they are not to be taken as legal advice.