Handling different products in the same batch
It is not possible to manufacture more than one product or variation at any one time.
If both products are manufactured from the same "source" material (i.e. two different sizes for soaps) then an option is to create a component to manufacture your complete source batch, and then configure recipes for the different sizes using proportions of the overall batch. This will mean you will only need to maintain a single recipe to produce your batch - your product recipes would only need to refer to the component material and the quantity consumed.
Example: I produce a fragrance and then package it into a 5oz and a 10oz jar. I would create the fragrance as a component with the ingredients listed, and then create a product with a 5oz and 10oz variation. The variation recipes would then contain 5oz and 10oz of the batch fragrance.