The Germans had not produced nearly 15,000 88 mm FLAK by 1942 and many were abroad, so the number in Germany has to be closer to half as many in 1942. But you are right, there were never nearly enough 88 mm and 105 mm weapons in the URSS, Africa, Italy, etc, Which only reinforces my low opinion of the Soviet and British generals being defeated by ridiculous numbers of artillery, tanks, etc,
I try to keep as broad a view as possible but find extremely interesting the effect of decades of brain washing on the Russians and British, who pretty much worship Stalin, Zhukov, etc, or Churchill, Dowding, Montgomery, etc, respectively, despite their obviously dismal performance.
Let me put it differently, had Churchill not wasted a fortune building slow, 4 engine bombers, more deadly to the British crews and German children than to German industry, but produced enough fighters and ground support planes, he would have wiped out the axis from Africa and Sicily with minimum tank and personel losses a year before the Americans had to come in to do it for him. He would have also kicked the Japs out of Burma late in 1942, allowing supplies to feed and equip millions of Chinese soldiers, which reinforced by Indian and American troops would have kicked the Japs out of the continent and allowed the Americans to bomb and blockade Japan in 1943 from a short distance, instead of in 1944 from a very long distance and after having to conquer a lot of useless islands. Had Stalin produced much better generals, planes and pilots and half as many tanks, he would have gained air superiority and wiped out the German tanks without having to make 36,000 Sturmoviks. Only the Americans understood the paramount importance of making high quality planes in large numbres to win the war.