STEP 7: DUPLICATE THE LEFT LENS LAYER
Now go back to layer panel and activate the left reflection layer. Now press ctrl+J/cmd+J to make duplicate copy of that. Now you will see that the same situation that you have encountered in step 4. I guess you remember the solution. Press ctrl+alt+G/cmd+option+G to clip the undesired portion.
Now change the blend mode of the newly duplicated layer to multiply to darken the image. Simply reduce the opacity of the left reflection copy. Just in case you want to increase the darkness then reduce the opacity of left reflection.