People (in this language) read from left to right, so they're used to what is on the left coming before what is on the right. If you have a time series that keeps growing, trim or scale it to the display size, or change the sample rate, or give some UI options to let them vary those parameters. Don't ask people to invert their expectation of "before" and "after". Those are too fundamental.
I agree that the presentation using a horizontal scrolling table is not the best. Maybe a vertical scrolling table with the x and y switched would of made more sense.