How to setup Operating Time properly

While adding processes to a BOM currently I and setting the Operating Time to 1 but actually different machines has different capacity so based on the machine on which a particular operation is going to take place the time setting will differ.

For example in one operation the time it takes to process one piece of an item is 1 second while in another operation a collection of items (that is 196 items) are processed at a time and it takes 10 hours.

So how should I set up the Operating Time in BOM Process?

Regards,