Post this question in the AT&T Direct private forum: »AT&T Direct
where you can get the true word from an official AT&T tech. This a secure private forum so if it is possible to switch your line to interleaved then you can also post your phone number/account number and they can make that happen as well.
Frankly I've never heard what has been explained to you and it even sounds a little nutty. Normal DSL is supposed to automatic revert to interleaved if the lines are of poor quality and the error rates are high enough.
Much of IPDSLAM DSL is on interleaved and all of VDSL broadband and IPTV is on interleaved. Why doesn't that cause problems for those customers?
Anyhow, good luck.--
TCE Weather -- Mt. Rose Cam