Whatever boxes are on the cable is not really relevant (and FWIW, they don't really serve a purpose either).
If the equipment supports the balanced standard, then you can use extensions all you like. If the equipment does not, the results are less predictable, but in your case no difference is heard so the answer is 'you're good to go' :)
If the equipment supports the balanced standard, then you can use extensions all you like. If the equipment does not, the results are less predictable, but in your case no difference is heard so the answer is 'you're good to go' :)