I am currently finishing the set up for an L842-MHX, 7', that is rated for 8-15 test and 3/8- 1 1/4 lure weight. I am using 15 lb braid on a 2500 Shimano Symetre reel. While test casting with tape (25, 16, 10 & 7) and rubber bands cut from tubing on all the 6's I notice that the #s 3,4 & 5 guides from the top, all 6's, are shifted to the left side of the rod and even towards the top after a fairly strong cast using a 1 oz. weight. Does this indicate that the guides can or should be rearranged? The distance and accuracy indicate that the current placement is very effective. Just wanted some opinions before I perm attach the guides. This has happened before and I didn't think to ask on the forum. Thanks.

No
This indicates that on your back swing the loading of the blank with the 1 once weight is causing the guides to want to shift to the opposite side of the blank because they are the leverage point

The same as if you had guides on the top side of a bait caster and pulled tensioned on the blank using the line, towards the bottom side would case the guides to shift towards the bottom.

Try holding them down with some 1/4" tape.

Bill - willierods.com