Generally speaking SACDs do have a lower volume during l\playaback. I have found that to be the case with most, if not all, of my SACDs.
My pre/pro, the TACT TCS MKII, is on of the few that will actually allow you to apply bass managment to the LFE channel of a 5.1 SACD or DVD-A recording. It does, however, use the ADC6 to the AD conversion on all 6 channles.