Like Rick said, the formula used by SAS is the same you linked to in Hyndman's book. They are standard definitions. Note that the link to the Visual Forecasting documentation he provided is for the weighted statistics across a group of series. This is the link to the documentation for a single series. It doesn't change much though, as they are obviously related.
https://go.documentation.sas.com/?docsetId=vfug&docsetTarget=p0uawamu7dmtc2n1cllfwajyvlko.htm&docsetVersion=8.4&locale=en
My recollection is that FS only shows the weighted statistics over all series in the forecast summary, and maybe only WMAPE. I don't remember if it shows any other weighted statistics.
If you are looking for the out-of-sample value of the statistics, you need to look at the FORECAST region. See also this:
https://go.documentation.sas.com/?docsetId=etsug&docsetTarget=etsug_esm_details10.htm&docsetVersion=15.1&locale=en#etsug_esm001158
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