So there is a bit at the end of the feat that says:
Special: This feat can be taken multiple times. Each time it is taken, the creature can apply it to a different one of its spell-like abilities.
emphasis mine
Now I take the can there to mean that you can, and are probably expected to use the feat on another spell like ability, but if you wanted to you could use it on the same spell like ability, and get another three uses of it as a swift action.
Am I right, or is there some ruling or some such that says I'm wrong?
Yes, you can apply it to the same spell like ability each time you take it.
Compare with Weapon Focus, which must be applied to different weapons each time:
Special: You can gain this feat multiple times. Its effects do not stack. Each time you take the feat, it applies to a new type of weapon.
Cool thanks, that really makes it a neat feat for clerics.
Cool thanks, that really makes it a neat feat for clerics.
For some of the domain powers?
Indeed, there are a lot that are worth two feats to quicken 6 times, at the moment I'm thinking of the bit of luck power in the luck domain for a more attack roll oriented cleric.
The Repose domain's 1st level ability, Gentle Rest, is my favorite. Stagger someone as a swift action and put them to sleep with your standard action regardless of hit dice.
These are some of the better 1st level SLAs:
Chaos - Touch of Chaos (1st), target takes the lesser of two d20s
Darkness - Touch of Darkness (1st), target suffers 20% miss chance
Evil - Touch of Evil (1st), target is sickened
Good - Touch of Good (1st), add 1/2 your cleric level to most d20 rolls
Luck - Bit of Luck (1st), target takes the better of two d20s
Madness - Vision of Madness (1st), add 1/2 your cleric level Attack, Skill, or Save rolls and subtract 1/2 your cleric level from the other two (works as a buff or debuff!)
War - Battle Rage (1st), add 1/2 your cleric level to melee damage
Very few of the 4th level SLAs are worth a feat at 16th.
Travel - Dimensional Hop (4th), swift action teleport
Magic - Dispelling Touch (4th), Dispel Magic
Weather - Lightning Lord (4th), a swift Call Lightning against a number of targets equal to your cleric level within a 30' radius just sounds awesome