Host Engineering doesn't make the D0-DCM, Koyo does. There was a minor issue in DirectSOFT 5.2 when configuring the D0-DCM, but that was fixed in 5.3 (free maintenance upgrade that was just released), but that had nothing to do with the actual execution of the AIN instruction.
Do you have any more detail from ADC Tech? If it really is an AIN PLC or D0-DCM firmware issue, they should know the status of the fix.