A few formatting nuances

Jeff writes in with a couple questions:

Mr. Bitter Script Reader,

Please, "Mr. Bitter Script Reader" is my father.

You can call me "Doctor."

Let me start by stating how depressed I was to find you are not repped.

After a joke like the one above, are you still surprised?

If you don't have an agent, well, let's just say it doesn't make a poor amateur like myself feel better. Good goals though.

Is it distracting to the reader to incorporate different screenwriting styles or does it add to the style of the script?

I've been reading a ton of screenplays lately. A move I should have made before I even attempted to actually write one. I noticed how some writers use different tools to convey the same meaning.

Example: when stating the age of a character, some choose (21), while others go with the simple, 21.

I'm sure there's a Formatting Nazi who's even more rigid than I who will cringe at this, but I'm not sure it makes a great deal of difference. I've seen both, though the (21) format is FAR more prevalent in the pro scripts I read. Either one is preferable to not including the age at all, or saying "She's 45, but looks 30" which is a maddening description that leaves me wondering "So who am I supposed to imagine here, Sandra Bullock or Katie Holmes?"

He continues:
Another example: when transitioning, some simply end the sentence. Start a new logline. Others will give the ol' ... at the end ... then use a simple logline like "KITCHEN", bypassing the "INT" and "DAY".

Misha Green uses it a lot in Sunflower.

Goes into the ...

DINING ROOM

... where Eve is setting the table with plastic utensils.

What do you think? If I give character names or just transition from scene to scene using different techniques, is it too distracting, or is that what people write about when they write about style? I'd hate to think I have to stick with one way throughout the entire script.

Minor point: you're actually talking about sluglines not "loglines."
I tend to favor the full sluglines, and again I see that a lot more in the pro scripts.
I hesitate to bring up secondary sluglines because I've seen instances on other boards were doing so conjures up all sorts of raving madmen who have such raging hard-ons for secondary slugs that they drag you into a fight about style, to the point where just engaging them ends up escalating the debate to such a degree that YOU end up sounding like the crazy one.
Here's my personal rule of secondary slugs: use them only in cases of sub-locations within a larger set. Example:
INT. BALLROOM - NIGHT
The wealthy mingle and socialize, as JAMES VANDERMEER (30) makes his way to...
MAYOR SWANSON'S TABLE
He sits down, then looks across the room at...
SENATOR BIGOT's (pronounced Bee-Go) TABLE
Now, my feeling is that one room in a larger house doesn't count as a sub-heading. So I'd write INT. DINING ROOM, INT. KITCHEN, and so on.
At the end of the day, though, these are really, really minor nuances. Using the wrong font is a much bigger deal than alternating between either of the options you're asking about above.