I don't see a diagram on page 13, but I read a few pages around there. I don't see anything about it not applying to micro-enterprises. I see one diagram (PDF page 14/page num 11) that says a farmer selling "under own name or trademark to end user in another Member State" (without saying there's an exception for a micro-enterprise) means that the "Farmer is producer," which sounds like the opposite of what you said.
There is a diagram on page 12 that says companies that use unbranded packages OR that use branded packages but are micro entreprise are not considered as "producer" of the package
After re-reading, it only specifies the packaging manufacturer is the producer when they are in the same member state as the seller.
If the seller sells to other member states I don't know
Not a diagram but the section on page 9 regarding who's considered the manufacturer is relevant here. For generic packaging that's the manufacturer of the packaging.