Sweet treats bakery question from past paper 2016

They should be ranked by the return per factor hour in mixing.
For Brownies this is (1.50 – 0.25) / ((20/60)/40) = 150
For Muffins this is (1.40 – 0.15) / ((16/60)/30) = 140.625
For cupcakes this is (2 – 0.25) / ((12/60)/20) = 175

Therefore they are ranked Cupcakes, then Brownies, then Muffins.

However, of course, the maximum demand for cupcakes is 100. This would ‘use up’ 100/20 x 12 = 60 minutes.
The have to make 20 Muffins (the minimum demand) but because they have to be produced in batches, they must make at least 1 batch of 30 units. This ‘uses up’ another 16 minutes.

This leaves 120 – 60 – 16 = 44 minutes of mixing, which will be used to make Brownies and is enough to make 2 batches (taking 40 minutes). 2 batches is 80 units of Brownies.
Sir! this question above is literally giving me headaches.
The above solution was written by you previously on this forum and i just copied pasted it.
What i dont understand here is that we ranked first to make cup cakes,then brownies and then muffins.But why when allocating the total 120 minutes we have on the bottleneck which is mixing ,you jumped to muffins after the cup cakes?Arent we should follow the order for allocating minutes which is first make cup cakes,then brownies and lastly muffins?