How are you recording your AA prompts?
Try using a more advanced script, rather than the default AA (system) script.
Especially, if you plan on recording different prompts for business hours and closed hours.
im using aa_sbcs_v04 and it works well.
i've enabled record prompts from handset.
from there you can overide the default AA greeting as well as record your custom prompts.
once recorded you can choose them from the AA setup window.