Murder's Mark - Ika Stealth & Sphinx length of show

[GM Khouri]

Does her listed stealth (+9) include the cloak of elvenkind? It seems low - I get +2 DEX, +1 rank (could have up to 4 but who knows), +3 class bonus because bard = at least +6 without the cloak, could be up to +9 if she took a rank at every level, but the cloak gives +5, so the total should be at least +11, right?

Right now, based on my math I'm assuming the +9 does NOT include the cloak.

ALSO it says The Lair with the Sphinx shows only last as long as she can keep up Minor Image, which says concentration +2 rounds and her concentration is +7. HOWEVER 9 rounds is only 54 seconds - do they really limit the Sphinx "shows" to less than a minute? That seems incredibly short and suspicious. Maybe it is supposed to be suspicious.

[Pirate Rob]

What does the concentration bonus have to do with how long one can concentrate?

[Philippe Lam]

The concentration bonus only influences how the caster is still able to throw the spell while being threatened in melee, or taking damage. This has nothing to do with how long it lasts. The concentration duration if there's one is directly written in the spell.

[GM Khouri]

Ah, so I guess the part I got wrong was "concentration" vs "concentration bonus." So if I have this right, she would still roll her concentration every round (well technically whenever she gets hit or distracted) and when it fails, the spell will linger for 2 additional rounds, yes?

I was confused because I read it as:
"Duration: (concentration + 2) rounds"

not
"Duration: concentration (+ 2 rounds)"

[FLite]

Only when she gets hit or distracted.

Beyond that, Like anything else "How long can you keep this up before you get tired / distracted" is a GM call.