Same AT&T plan and same issues. How are your speeds in other locations? Something is definitely wrong.
In either Northern or Southern CA I am getting the same results, it has happened rather suddenly. About six months ago this same test produced speeds that were nearly identical to the T-Mobile speeds posted here. Each time I test I run ten of them back to back concurrently.
A call to AT&T was met with courtesy, cooperation and a promise they'll get back to me in 5 days, so we will see.