I just took on a Chinese chain acct. they want the exhaust hoods cleaned quarterly, after 30 man hour on the first job Im debating whether or not this was a good choice... The bells and ducts appears to have been over looked on the previous cleanings and was where we spent the majority of our time, but the hood it self was a snap. Is this normal? The facility Mgr. assures me that once down to metal and cleaned on schedule these shouldn't take more than 8 man hour to clean. Any ideas?