That can't be right. I've got Atom bombs in 1940 as germany, AOP3 BETA2. Albeit it's in Open Play and I have a few more cities than I might have otherwise, it still seems very much too fast.
Also, the Atom Bombs themselves build way too quickly. Their

cost needs to be multiplied by 1.5, or doubled. Takes 4-5 turns (less than infantry) in most of my cities for a weapon that destroys russian stacks of 100+ units in two hits.
And about those Russian stacks, I noticed that in the newest version the USSR does not even build one single tank. They'll send stacks of 100+ infantry, and maybe 2 or 3 planes, but never an armored unit. Perhaps the enlarged build times are dissuading them?