amps and volts

So, after much preparation and work, i finally got the panels installed, and all the "other stuff". When i was running my MC4 wire ( which by the way, I don't understand why they don't make it like an extension cord with 2 wires together, so you're really running just 1 wire instead of 2 "separate wires), but anyway, as I was running the MC4, I kept marking my "plus" wire so when i got to the end I would have my polarity correct. I realized that I didn't have to do that, but all I had to do was a continuity check by bringing the end of the MC4 up to the panel and marking just the end when i correctly had the continuity. After I did this, I put my meter on the ends of the MC4 just to look at what I was producing in the way of volts and amps. I "assumed" that I should put the plus from the meter to the plus wire and same with the negative. I did that and got a reading. But......to my surprise ( not an electrician here), I got the same reading off my meter when I switched the wires from my meter and put the plus (red) from my meter to the neg MC4 wire. So I got the same readings off the panel into the meter no matter if I put pos to pos, or... pos to neg. Again, not an electrician here, but does that sound right. Doesn't sound "logical" to me. ????????