Why do you think it take until the IPO closes?
That's how I interpret the wording, but have no definite confirmation. AMHash3 shares are converted to AMHash1 at end of IPO, which for direct shares seems reasonable to be done in one single step to prevent extra fees (direct->AMH3@HL->AMH1@HL). I might be wrong here, but would not like to risk buyers to have to wait weeks for their shares.