Answer for My soil ph is already fairly neutral due to liming for several years. Should I still use the plotstart? What benefits will I receive?

YES! There are couple reasons. Fairly neutral means that there is room to improve. Any bound up lime particles will be broken down by PlotStart and release more calcium in addition to what is in the PlotStart product. But for most fairly neutral is good enough, right?
WRONG – If you were crazy enough to take a sample next to the beach that consists of mostly sand guess what you will see? Neutral pH! But it isn’t the sand that keeps things from growing its the lack of calcium which should make up 70%+ of the saturated macro-nutrients in the soil for plants. So even though a pH reading may be close to neutral that doesn’t mean calcium is available to the plant. Your soil test can also show calcium is there, but it could be bound to soil particle and inaccessible by the plants roots. PlotStart not only provides soluble and available calcium right away, but it frees up those bound atoms so the plant can use them.