This is one of those intended features that didn't quite work out. I am fairly certain that MM originally planned for the various scanners to be different, but due to AI problems, nixed the idea in beta. Of course, I was not a beta tester, so I may well be wrong on that.
Also, where are you getting Gravitic and Tachyon scanners being in the same tech path? Tachyon require Sensors 4-6, which requires Physics 1. Gravitic requires Gravitational Technology 1-3, which reqiures Astrophysics 2. They are not at all on the same tech path.
[ September 15, 2003, 21:12: Message edited by: Imperator Fyron ]