The Pivot-Point Weighted MA is very different from other weighted MAs, in the sense that the price weights can achieve negative values. For an example, if a length of 21 is used, the pivot point will be calculated as 13, meaning that the 13th prior candle will have 0 weight, and all prices before it will have a negative weight on the sum, so their impact is reversed rather than just unweighted.
The intent of this is to reduce lag by front-loading the prices. It works better in cyclic markets, and with a longer length, where the inflection point (the one with 0 weight) is aligned with the cyclic turn.
You can configure where the weight starts. If you leave it as 0, it will start with floor(length * 0.66) - 1.