I have been performing nonsurgical lip augmentations with fillers for well over three decades, since the early days with the original Zyderm I collagen filler. More recently, hyaluronic acid products, especially Juvederm Ultra Plus XC have proven quite useful for producing very natural looking results when performed by experienced injectors. To prevent the production of "duck lips" (aka "trout pout"), injectors must respect the appropriate proportions of the lips both in frontal and profile views. Ideally, in volume, the upper lip should constitute approximately one-third of the total volume of both lips together, and, in 90 degree view, the upper lip should extend 1-2mm beyond the pout of the central portion of the lower lip. I literally just performed a nonsurgical lip augmentation with Juvederm Ultra Plus XC on a female patient in between drafting the answer to your question. Rather than a by-the-syringe approach, sophisticated injectors must respect the above lip proportions and try to achieve them, regardless of whether it takes one-half a syringe or 1.5 syringes to do so. In other words, experienced professional physician injectors should quote fees according to the job and not according to the syringe, just as a professional surgeon would be expected to quote a fixed fee for a particular type of operation and not charge, as in a flea market, "by the syringe." Make sure that you consult with a board certified aesthetic physician and be certain to ask to see his/her before and after photos before agreeing to proceed. Best of luck.