In the player book the success level of a skill check is described as:

no tengwar, narrowly successful

one tengwar, great success

two or more tengwar, extraordinary success.

This being said the following paragraph to this information says something about a 'superior' success should be worthy of memory in song or tale. Is this being used solely as an adjective or is there a level of success that is superior? If used only in a descriptive sense, what success level is superior? I would assume that extraordinary plus is what they are referring to considering the way this level is described as being 'memorable'.

Further I notice that the target numbers are apparently modeled after a skill level of ***(level three). There is no mention that I have yet found that deals with those of lower skill level. Is there supposed to be modification to these target numbers for lower skilled attempts or for that matter higher levels, otherwise why is it relevant that the character is hale and has skill level 3?

Its solely as an adjective.

Skill Level 3 TNs provide you with a base line for all Skill Levels and there is no modification for other Skills Levels. For example, if you have Skill Level 2 and go up against a TN of 14 (which is average for SL3) you can expect that it will be harder than average.