That's right. The internal filters use a slightly different conversion of time period to a: 2./(1+Period). That's the usual 'smoothing formula' that is also used for EMA and other accumulating indicators.

The filter is the same, only the time period is different. I believe in the tutorial 1./(1+Period) was used for better explaining the int/var issue, but I think we'll also change the tutorial to the more common formula.