Barbelface:Would I benefit from a higher level putter?
It would be rather difficult to say, imho... you appear to have only played 3 ranked rounds with nothing current to base even a hypothetical guess at what may be a weakness in your game … and you state the current putter is "serving it's purpose."
If there is something holding you back, it may not even be putting but rather approach shots, proximity to hole, scrambling or something else, just hard to know given such a small and infrequent sample of rounds played...
Since the greens stay the same as you get promoted but just speed up.. any putter that you are comfortable with and use well is likely sufficient... buying a better putter won't automatically make you see the line better or get the right speed.
some players prefer lower to mid range putters because they serve a miss ding putting style well from what I have read and understand. And there are a few players out there that stick with the starter putter for quite a long time...
So it can really depend on what you want to spend your credits on.