Terry,
Especially with the Sl version don't just set the height of the launcher at full draw and forget it........you ALSO have to make sure that the arrow is centered within the cage itself at that same height. Yes it is easy to have the height set correctly but have the arrow centered high or low withing the cage causing a conflict with your fletching.

I just set one up on a friend's Allegiance the other day and to get the launcher height I wanted and keep it as close as possible to the arrow shelf without hitting the edge, to get the arrow perfectly centered within the cage I had to slant the entire bracket downward about 10 degrees.
Don't just assume that teh arrow is flying through the center because the rest of the set-up looks good.

By hand pull the slide back until the arrow lifts into position, with your other hand hold the arrow in that position and let the rest fall away........now look to see if the arrow is centered properly at rest. This is the position that is most critical and what it looks like when the fletching reaches the cage.