Your estimate of alien sensor is based on a guess because you can only detect the strength of the active element of his active sensors, not the EM element. I think the estimated range for aliens is based on an EM strength of 10.
Yes, I'm pretty sure that his sensor tech is way better than mine. I just did'nt know that I could get false readings like that, it's pretty cool actually.
I survivevd with only one scoutship biting the dust anyway, but I was a little confused. Rightly so I guess.
I had a strange battle were an enemy could somehow target my ships with no active sensors to track me. I had a scout very close to his ships and detected a resolution 20 sensor.. This had no range to my ships,far from it. I turned tail and started to run and they followed. They were able to keep pace since they were slightly faster than my ships. I never managed to detect any active sensors except the res 20 one. I'm also pretty sure they did not use active or passive sensors on their missiles. The first run the hit my TG when it were picketing in space with no sensors on and I do have decent passiveso I should detect any active on the missiles.