ok heres the skinny on these spells. first off they can only be bought from Adventure vendors when you have enough points earned from completing LDON adventures. they can Only be bought in wayfayrer camps.
Secondly they have 2 different lines of spells. the first ones detect, disarm, and open holy traps. the second line detect, disarm and open magical traps (thieves are needed for mechanical traps).
augury detects a holy trap lock
cleansing disarms a holy trap lock
excorcism opens a holy trap lock
you have to sucessfully cleanse the holy lock item before you perform a excorcism.
apprasial detects a magic trap lock
discombobualtion removes a magic trap lock
extrication opens a magic trap lock
you have to sucessfully discombubulate the magic lock item before you perform a extrication.
test apprasial and augury on known none trap items to see what the message is, you will know if it works as its a different message. also if your using the lessor spells in a high level dungeon they may not work also. (not sure on what they would cover but i would assume the lessors cover 20-30s avg. party level, the normal (lvl24) spells cover the 30-40s level, and the greater would cover 40s+..but these are just estimates and HAVENT been confirmed).
The reasons the spells are lower than 20 is that you can obtain is technically at lvl 15 you CAN go into a dungeon if the total party avg. level is 20 or above..but you have to be withen 7 levels of eachother so that means that this would be very hard to do..ie have like 5 lvl 21 to 22 players and one lvl 15 player in a adventure group(avg 20). You may just want to wait till your 24 and buy the normal spells instead of using adv points on the lessor spells.
if both apprasial and augury do not detect that the lock is traped then it could be a mechanical lock. thieves and bards are needed for those.