Hm, great post erpel. Please post more so I can learn more from your elaborate posts ^^

Correct me if I'm wrong, but this is what I'm thinking.

settecba, you say that you have higher EV since you'd get 2nd pair hands to fold to your semibluff on the turn right? But how often will the villain fire a 3rd barrel with 2nd pair after you called down two streets? Right now, you potentially have 12 outs (3 kings, 9 flush cards) as well as 3 aces that can be bluff outs, since you can very well be drawing to the nut flush. There's also a lot of random brick cards that can shut the villain down since you called down two streets (if he has 2nd pair and puts you on a Q). If you call the turn, you're probably going to bet around 2/3 of the pot on the river if checked to, which would cost you just about as much as your semibluff on the turn, but with an addition street of information.

Also, if you only call the turn, you can keep the pot smaller. So in the case that a K falls on the river, the pot will only be $4.75 and he bets say $2-3.50 (or maybe even less like his turn bet), and you feel that you have a chance of winning a showdown, you can call stand to lose less money. Whereas, if you semibluff the turn (say $4), and he calls, and the river comes a K. The pot would be $10.75, and he bets, would you fold or call? Or if he checks to you, on the river, are you going to check behind and give up? It seems to me that if you semibluff the turn, you will discount your K outs, as they will put you in a more difficult position on the river.

Now like Fnord said, if the opponent is more aggressive in that he may bet with a wider range of hands, I may be opt to raise the turn more often.