Good catch on the complex action type. I've previously seen people claim that it's not an action.
Yeah, I've fallen into that mind-set before, myself. Didn't realize for the longest time that there was a Complex Action titled "Use Skill" that covered any non-specified action skill.
Arguably, you could build on an improvised Complex Form, because after the first threading, you're no longer creating it "from scratch." I'm not sure which way is intended.
The argument exists, and there's nothing to really say you can't, I suppose, but I'm not sure I'd let people use it. With a good pool to resist Fading, that makes it even cheaper for Techno's to get their complex form up to Resonance *2. Drain = Hits applied to the Complex Form, threaded rating is only used for Stun/Physical determination.
If I've got a DP of 9 for Fading, and I'm not under pressure, here's how it would go:
1. Thread Attack (currently at 0), discard all but 2 hits.
2. Resist Fading DP(9)=3 Hits, 0S taken.
3. Thread Attack (currently at 2), discard all but 2 hits
4. Resist Fading DP(9)=3 Hits, 0S taken.
Repeat, except change "0S" to "0P" once the threaded rating exceeds Resonance, until the threaded rating equals Resonance *2.
Even if you apply the penalty for sustaining a complex form to the Fading test, that still gives you 2 average hits, you just keep 1 hit each time and keep trucking.