For the 1000th time.
1) The VPI/VCI settings have nothing to do with your issue.
2) Your downstream rate is trained at 1/2 Mbit, you're downstream rate is 576K with a 128K upstream. This is slow
3) Your SNR value is tragic, you have a noisy line, which may explain why you're training to the DSLAM/RT at such low speeds (DSLAM rate adapt)
4) Your line attenuation is pretty high, you must be far away from the DSLAM/RT. It's high, but not as big of an issue as your SNR.
You're wasting your time with any other investigations