advantage to kickoff out of bounds, am i missing something here?
 

okay, so in HS, the normal kickoff line is a team's own 40 yard line...

let's say we're in TX and playing under college rules (with some modifications like the 40 yd line for kickoffs)

I think they no longer do the 5 yd penalty for kickoff out of bounds, it's just straight up 30 yds from the spot of the kick now...

now after the last scoring play (PAT) the defense commits two a dead ball unsportsmanlike conduct penalty that will be enforced on the kickoff, so now the team that just scored (now the kicking team) is kicking off from the receiving team's 45 yard line...

if a kickoff out of bounds is 30 yds from the spot of the kick (assuming the kickoff went further than 30 yds) wouldn't it be more advantageous to aim the kickoff out of bounds at like say the 10 yd line rather than just kicking it through the end zone for a touchback? If the 30 yds is enforced from the spot of the kick then wouldn't the receiving team have to take the ball at the 15 yd line then?

What if the kickoff was from the receiving team's 30 yd line? (possible from two dead ball 15 yarder penalties on the receiving team b4 the kickoff)

most coaches i've spoken to about the rule say the ball is placed on the 40 yd line no matter what but I believe they're mistaken since they've been either watching too much NFL/college or don't really know what the rule is...and coaches aren't really known for knowing the rule book in depth...

i know this play doesn't come up too often (probably as rare as a 4th out appeal in baseball/softball) but it's the one play that I can't seem to get a clear answer from...

You are mistaken in the college rules. So, unless Texas did an additional modificaition to the rules (other than what you stated) they can enforce 5 yards from the previous spot or 5 yards from the dead ball spot where the ball subsequently belongs to team B. I'm just replying regarding NCAA rules. Texas officials will need to chime and and indicate whether the 5-yard part of the penalty has been removed. If the only modification is the restraining line, then there are additional options.

Not in Texas either (heck, I'm not even in the US) but I do work NCAA Rules.

My guess would be that Texas changed the kickoff line from the 30 to the 40 due to their younger age kickers. I'd be a little surprised if they messed with anything else.

So as ljudge already stated, the receivers have multiple options:-
o take the ball 30yds ahead of the kickoff line ie the receivers 30yd line
o push 'em back 5 make 'em kick again
o tack on 5yds from the spot it went oob
o technically a 4th option is to decline the penalty and take it where it went oob, but you would never even offer that option, it would only confuse the captain.