The writeup for Solarion's Onslaught specifies a difference depending on whether you have the Flashing Strikes class feature. Am I being dense? How could you get a 13th level Solarion class feature without getting the 7th level one?
Future Archtype options may remove it. This coverall language is used in a few cases in classes where their ultimate ability requires something prior that could be missed by an Archtype or by multiclassing. It also may be loosely going the opposite way, in that this ability works with Flashing Strikes but not with say the multiclass abilities of a Soldier/Solarian.
Ah cheers. I thought archetypes always swapped out the same levels. Future proofing makes sense. Thanks.
it also might cover some future multi-class type feats that allow you to pick some class abilities, so you don't get onslaught without flashing strikes and somehow expect to have flashing strikes for free or something.
Basically, what you said, future proofing
SOLARIAN’S ONSLAUGHT (EX) 13th Level
When making a full attack, you can make up to three attacks
instead of two attacks. You take a –6 penalty to these attacks
instead of a –4 penalty. If you have the flashing strikes class
feature, you instead take a –5 penalty to these attacks as long
as they are all melee attacks.
EDIT: It looks like you don't need Flashing Strikes, but it's good to have anyhow.
Yeah, I didn't mean it was a prerequisite. It just seemed odd to outline what happens in a corner case so rare that it literally never happens.
Isaac and gustavo have probably got it right - potential archetype and/or multiclass shenanigans.
It occurred to me that perhaps Flashing Strikes used to be at 6th level - and as such was swapped out in the case of Solarions with Archetypes. Maybe the Solarion's Onslaught feature was intended to be slightly worse if you weren't a "pure" Solarion and this just didn't get caught in the (hypothetical) edit which moved Flashing Strikes from six to seven.
Makes sense. Thanks, Owen.