Almost, but there's a little error. "The setting is"... "the levels are". The verb matches the subject. We understand that well enough, You're right in thinking that the ending is implied. English hates repetition, so there's no point in repeating what is already written, The implied ending is, "just as the light levels are saved in a step." There's no reason to make "step" plural, and "a steps" is impossible in English grammar.