If you acheived your goals and you had enough fuel to bring your periapsis down to what i assume is in the region of 55km then i would call the return a success?
Not sure I understand the statement, when i plan a mun return trip launcher my final stage is usually empty or jettisoned when i reach the desired periapsis. Unless you are planning to hop to another biome upon return I'd say mission complete.
In career mode wasted fuel will cost you so you are doing the right thing. A few passes over kerbin is time consuming but cost effective.
