The Zechus Hakohanim

Rashi on בהעלותך את הנרות says that your job is greater than theirs because you [Aharon Ha-kohen] מדליק ומטיב את הנרות - light and prepare the candles.

Questions:

A]  הטבה precedes the הדלקה so Rashi should have said שאתה מטיב ומדליק?

B] The Rambam paskens that even a non-kohen [known to talmudists as a זר] may carry out the הדלקה so what is the special zchus given to Aharon and the kohanim here?