I am hoping to be able to replace existing lever shower handles. The only problem is that I can't get the old ones off. I removed the set screw but the handle will not budge. Not sure why. I have the same handles on a sink and in this case, as soon as I remove the set screw, the handle pops right off. When examining the shower handles and sink handles closely, it appears that on the shower handle assembly, there is an extra metal component that the lever attaches to. I have attached photos of the handles. Any suggestions? Thank you!