Weekly Price Level

A screenshot showing exactly what you have in mind would have been very helpful here.

Let's see if I understand this correctly.

For a chart set to weekly time frame, you would like a horizontal plot to display a value based on the current week's opening price, times 2%. You would like that plot to extended for the entire length of chart. So one value based on the current week's opening price, is plotted for the entire chart.

If this is correct, then the last bar on the chart contains the value we need to base our computations. The code that follows includes a user adjustable input so that you can adjust the percent value used to compute the plot. This code can be applied to any time frame and the code will always base the computations on the opening price of the last bar on the chart.

input percentThreshold = 2.0;
def lastBar = !IsNaN(close) and IsNaN(close[-1]);
plot weeklyOpen = HighestAll(if lastBar then open else Double.NaN) * (1 + percentThreshold * 0.01);