What're factory adjustable rockers worth?

When I was in auto mehanics school in the early 1970's I worked on a slant six. The adjusting screws were a bit loose & the instructor had me tighten them by flattening out the hole in the rocker a bit. Don't remember if we used a hammer or just squeezed them in a vise but it worked. This was on my mom's car & we held on to it for a few more years. Don't recall ever having a problem with them needing adjustment more than usual afterward. Not sure if this is a Chrysler/Dodge/Plymouth approved repair method.