Odoo expects you to create the lot on the manufacturing date, so that lot.create_date == manufacturing_date.
There's an OCA module that adds the manufacturing date to the lot, but I'm not certain it changes the calculations to use that new field instead of the create_date

There can be an issue with how Odoo calculates the Expiration date. It uses data / time of lot creation. And not manufacturing end. Let say you create the lot number on manufacturing day one, and the manufacturing process takes 2 days, the expiration date will be calculated on Lot creation date/time, and not Manufacturing end date/time. So dependent on your business process and requirement there might be an issue.
In such a case you should be able to recalculate the expire date (+ best before etc) with an automatic action triggered by the manufacturing order completion.

And btw: There is a field named "Removal date" on the lot, and it seems it is equal to Manufacturing end date (not confirmed).