6: 2.486 (kOhm)
7: 3.020
9: 3.022
10: 2.488
B3: 2.985
B6: 2.991
Center pin Left: 87.3
Center pin Right: 98.4
I don't see that any of these are off. 2486 Ohms is very close to the specified 2500, etc. Nothing to worry about here.
1: 81.6 (V)
5: 80.6
A1: 80.6
A6: 81.6
B1: 81.6
B4:80.6
As mentioned in bold and red lettering on the voltage check prompt, it's mandatory to fix resistance issues before turning an amp on. Having said that, all these voltages should be between 75 and 90, and they are, so nothing to worry about there.
I was wondering what could cause these differences, if the big 10kOhm difference between center pins could cause anything noticeable, and if I could do anything about it (rewire ? change parts ?)
Carbon resistive elements have a bit of a wide tolerance. In practice, this difference is not audible (though some mistakenly attribute this resistance difference as the root cause of a potentiometer with tracking issues at low levels).