I never owned any other RD, other than my STi so I haven't seen TEC modes on other detectors.
However what I continuously notice, mostly with X and K falses that the frequency will often change. For example, it will go from 24.174 to 24.175, 24.178, 24.180, etc. Also, when I pass a known false, sometimes it will show as 24.185, and othertimes it will show as 24.19 or 24.175. Weird.
With police radar, it will show up as say 24.147 when the signal is vague. However when I reach the source it will switch to 24.150 or 24.145 and remain there.
Is this a bug with the STi, or is it common for the frequency to change due to distance to radar source, or changes in weather, etc?