Too bad you weren't able to get the codes off the TCU, most generic code readers cannot do that.

It is possible that the PNP is good and you got another error. Because this a 'new' car, your driving habits are probably different than the PO, AND the TCU goes through a 'learning' phase. A battery disconnect and grounding the TCU forces the TCU to go through another learning cycle immediately. What you did is drive enough after the ATF flush to allow the tranny to adapt to your driving. Let's hope that did the trick.

As for the 740/V70 city driving comparison, the V70 has a much larger turning radius, it feels harder than the 740 up front because of the FWD, it weighs a few hundred pounds more than the 740. But, those things make it a great highway cruiser.

Oh, make a point to change the cabin filter, most owners don't do that.
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My back feels better when I sit in a Volvo seat