Voltage delta between speakers

I am comparing two CD Players; my current Cary CDP-1 and Classe CDP-202 I just bought used.
Since they have different output Voltage I wanted to "balance" the loudness as I switch from one to another player. using Stereophile Test CD3 track 21...but in the process I discovered something that I am not sure is normal or not.

The manual in the Test CD says that once you get Voltage at the speaker terminals to 1 Volt and if there is less than 10% difference between two sources - I can ignore that and consider them being at the same Volume level.

How about actual difference between channels.... because this is what I noticed.
with Cary Left: 0.755 vs Right 0.732 (delta of 0.023)
with Classe, Left: 1.034 vs Right 0.992 (delta of 0.042) 

Those are very small and based on Stereophile comments that 10% difference shouldn't be perceivable.- might be normal ....but wonder if anyone else is aware / knows that there may be difference in Voltage output not ONLY between different components (which we all know) but also between channels of the same component.??

Thank you! 

PS: I have done those measurements multiple times....the numbers were very stable and constant.