Magic 4e Lightning Spells

[Eric Funk]

Greetings!

Lightning (GURPS Magic 4e p.M196) has a followup effect of HT roll or suffer stun.
Explosive Lightning and Lightning Whip mention specifically that the effects of Lightning apply. (Spark Storm mentions a (capital L) Lightning bolt strikes... Storm has a small l).

Spark Cloud and Shocking Touch explicitly mention only providing special effects against metal armor and/or electronics.

Wall of Lightning, Ball of Lightning, and most others in the college do not mention any side effects despite having "Lightning" or spark in the title.


Is there clarification anywhere as to why or is it just those four electric spells that have the followup stun effect?

Thanks!