TUV primarily applies to TripleA where the computer can easily add up the value of units on each side, and also runs simulations of battles thousands of time to see if you are killing more valuable units than you have lost yourself. The Allies start with a 573 TUV advantage and also are out-earning the Axis by a 2:1 advantage. Obviously the Axis is in a much better starting position than the Allies so the advantage rapidly disappears during the first 5-10 rounds.
There is no magic TUV number for the Axis to obtain, but certainly closing the unit advantage gap from 573 down to 300 is a good sign that you have done lots of good battles and improved your economy. I personally don’t look at the TUV gap and instead focus on the major objectives for each side: capturing Moscow for the European theater and getting India or Australia for the Axis. Obtain your goals on just one side of the map and you are in good shape regardless of TUV numbers.
1 note to the tripleA thingy.
It does count bases and factories as well so many islands in the pacific and some places in the atlantic have a pretty high value that nobody really uses.