You don't see most reviews test routing throughput at all, let alone with PPPoE.
SNB hasn't run our routing throughput tests with PPPoE because most readers are far more focused on wireless performance, so that is where we spend most test time.
Our current test suite it more comprehensive than anyone else's and it already takes too much time, causing fewer products to be reviewed.
So the technology to do the testing is there. It's a question of priority, reviewer skillset and return on investment for spending the time to do the test.
I want to be clear that I didn't mean to say your work here isn't valuable or appreciated, by far you have the most comprehensive tests for actually comparing products...as most of the "review" sites have individuals making up their own tests which aren't repeatable or consistent, so their is no threshold of comparison.