The butterworth filter line and the are plotted together by default. The values for the lengths, for both the butterworth filter and the raw data, can be changed from the format menu (through a toggle).
The shorter the Butterworth length, the closer the line is fitted to the raw data, however you trade of with more frequent slope changes.
The longer the Butterworth length, the smoother the line and less frequent the slope changes, but the Butterworth line is farther of center from the raw data.
Sorry to disturb, but I have seen that you have posted this question on get satisfaction few months ago https://getsatisfaction.com/tradingview/topics/return-close-price-of-entry-position regarding the return price of a long entry position, and I am scratching my head with this exact question for some days now. Did you find the answer to that question ?