couldn't agree more with doublespey's post!
I've looked over the XLT chart, read the comments on the 7141 above, and have now cast the 8/9 XLT (final version) and 9/10 XLT (prototype) on 8 rods by 5 different manufacturers, rods rated 9/10 through 10/12. I did not find that the line weights and rod weights matched at all. In almost every case I found that I liked the line/rod combination best when a lighter line weight was used. For example, the 8/9 XLT cast best on the rods rated 10/11 (on the 9/10 rod I tried the 8/9 line seemed to be badly overloading the rod when I started working the entire belly and I was afraid I was risking blank failure so I stepped up to the 10/11 rods and found for me the right match); I found the 9/10 line slowed most of the 10/11 rods down to the point where I did not enjoy casting them, and I will be surprised if I like the 10/11 lines on these rods if I already didn't enjoy the 9/10 line. These rods certainly were able to cast the 9/10 line, I just didn't enjoy casting the combination as much as the lighter line. The 9/10 line was a better choice for the rod rated 10/12.
When you look at Simon's charts for RIO he factors in the "feel" a caster prefers, and generally a caster who prefers a faster "tippier" feel will select a lighter line (a 9/10 line as opposed to a 10/11 line for a 10/11 rod, for example). I think the same thing is happening here. The XLT chart recommends the 7/8 for the 7141; Bruce prefers the 8/9; based on my recent experiments with the heavier lines, I might prefer the 6/7 on this rod (but won't know until I try it). I think an important question that doesn't seem to be addressed on the XLT chart is "how much line are we working with in making these recommendations?" And of course an angler's personal preference must be factored in here as well. It would make sense that the heavier line might be a better match for a rod if the expectation is that less than the entire belly is being lifted and cast, while perhaps a lighter line would be the choice for anglers who will be using the line at maximum range.
I think doublespey's point is well-taken: it is best to use any recommendation as a starting place, and if you can try the lines out for yourself to see what you prefer.