I will appreciate any advice with my difficult question. Our ISO (22716) certification inspector said "you shall have specific mixing times in your batch record". Anybody can help me with that requirement? I understand we need clear and measurable requirements but it would be somewhat challenging to meet that requirement in production, speaking operational way. Operators are not robots. I was thinking to replace let say mix for 1:45 minutes by NLT 1:45 and NMT 2:00 hours. I honestly can't find where the requirement says that you cannot have a tolerance. Any advice will be highly appreciated.