On the second line:
1)Much of the output expansion in the late war was from sources other than the transfer of resources from the civilian to the military sector within Germany. Heavy industry grew (though in 1942-3, not later) and millions of workers were added to the German economy, most of which weren't even available before Barbarossa and Hungarian Jews weren't available prior to 1944. The early war investment boom already produced some effect by the late war. As more production could have been done without this investment, to some extent there was more production late in the war because there was less early on. Some investments, of course, only showed their true potential after the war, and sacrificing investment for extra weapons in Barbarossa would have made sense. But the Reich wasn't preparing for Barbarossa in isolation, it wanted to spend just enough to win a quick campaign because the campaign itself was part of a wider conflict with the Western powers. Hence it invested long-term a lot and spared some effort for the air force and navy. If it expected to wage a war of attrition on land for several years it could have done differently, but then its geopolitical outlook would be completely different and it may not even have done Barbarossa.
Late-war expansion alone cannot be taken as a gauge of how much civilian potential was left to mobilize because these other factors must be discounted from it.
2)Some civilian production in the early war was not consumer goods but exports. This wasn't wasted production as the logic of the balance of the payments was still in place and German goods were needed to prop up and maintain allied states.
3)The German military economy's previous phases do not show any "slack" towards the civilian sector but a continuous drive to mobilization. In 1933-39 it went from almost nonexistent to a higher level of mobilization than the Western powers, so high it was causing economic problems. Never before had national production been redistributed on this scale or with such speed by a capitalist state in peacetime.(p.659). It was a strong and very effective reallocation, and the side effects were just natural for this level of mobilization. Interruptions in 1937 and 1939 were this high speed mobilization hitting the country's resource ceilings.
Then in 1939-40 mobilization had the most radical policy, to sacrifice not just civilian production but even the war effort's long-term industry to immediately maximize output. Already in the first winter of the war there were severe shortages of items such as ovens and stoves and the civilian industry -not just consumer goods but even electricity and mining- had large cuts to its steel rations. In 1940-41 the time horizon was reversed, there was now much investment for the future, but the stance on the civilian sector did not change.
In 1942 civilian coal was sacrificed for steel. In 1943 total war is formally announced, but since a decade before resources were continually migrating from superfluous civilian production to the military-industrial complex. There was a consistent movement towards total war. As the first graph in >>34051 shows the civilian sector shrank with every year. It was probably possible to accelerate the transfer, though that could run into
a limitation -the state's power- and hence it wouldn't be as fast as the Soviet Union's lightning fast mobilization as Germany wasn't a command economy.