In the late 1990s, mainstream, Big Pattern Company corset patterns still didn’t exist. A lot of the costume offerings fell short when it came to construction and accuracy. The Big Company patterns often went on sale for 99 cents or so, though. It made sense to pick and choose among them for pieces that could potentially be used.
The corset you see here was not a great waist training corset. It really is just an altered bustier pattern, but it worked. I don’t think Simplicity 9180 refers to the same pattern anymore, unfortunately, but you can find patterns like it as of the time I wrote this in Simplicity’s New Look line. This is good, because New Look is cheaper.