You are correct about that Persian air distance, my mistake. I had been looking at the Caucasus routing not realizing that the Caspian Sea-Kazakhstan route cut off a space. That saves half a turn’s worth of UK income.
That last game I had hopped an Africa fighter over and shuffled a mech in, but didn’t do a fighter build in the Persia IC because of the miscount. I had tried “overworking” the German air and main thrust by pincering two infantry forces through Bessarabia and Baltic States, and a Brit landing in Norway under cover of the surviving half of the Home Fleet (SZ 106 transport had survived G1 but went to Britain because I wanted to force Germany to buy defensive forces.) However, I found I still had enough German air plus late arriving mech/tanks along with a portion of the spearhead infantry to handle these, take Western Ukraine, retake Norway, while still continuing the spearhead to Belarus next to the main Soviet stack with mech/tanks, etc. in Bryansk. And the Scandinavian infantry took Leningrad/Novgorod.
R3 counterattack odds were very poor for Russia and were going to leave a tank stack that would still have enough mech/tanks reaching it the next turn to be unstoppable. So the retreat to Moscow was made on R3.
On G4 I strat bombed Moscow’s IC with three bombers. I decided not to scramble the two Russian fighters for this as I needed their defense as badly as the IPC’s. I figured the ~50% chance of losing one of two fighters outweighed the lower chance of clipping a bomber at ~33%. The IC’s AAA missed and the bombers inflicted enough damage that I had to spend several infantry’s worth to repair for a final infantry build there on R4, which was mostly a waste as calcs showed it would not hold even with some UK help. But I stayed and was bludgeoned. German tanks reached the Caucasus on G6 and would have been unstoppable. US landing and Brit round 5 stacks/w UK fighters reinforcing in Normandy were crushed on the counterattack that turn. It would have been much better to do a fighting withdrawal toward Persia, maintaining a threat to keep German support forces in theater, rather than be unceremoniously swept away.