If I'm willing to deal with a little extra complexity I run 2 loops. The delay goes in the regular loop (parallel mode) and the EQ-Tuner-Boost go in the Line Out/Line In. But I usually just put it all in the Line Out/Line In loop (EQ-Delay-Tuner-Boost).
I never really went any further investigating the regular loop in series mode. I was never totally convinced that it's not normal behavior for a 6100 and I didn't want to go on a snipe hunt, and I have a workable solution.
I was just setting it all up for a rare gig this weekend and man...this amp really kicks ass!