I have been maintaining also...it is tricky. Weight is subject to so many variables, it's definitely more of a seesaw than a constant, but there is something to be said for limiting the range of the variation. I've been back and forth enough to know my "comfort range" and if I get outside of that, I try to keep the calories under what I burn for a while (or, strange as it may sound, eat a bit more, if I go below my lower limit). It sounds like you already know what you need to do. Sometimes you'll be able to and sometimes you won't, but as long as you don't let it get too far, it's a fairly easy correction.
Congrats on your success so far, with the running and the weight and the body fat progress