WHen using the output sharpener there is a Merge option. What's it do? I thought it would flatten the image but it does not.
See page 6 of the PKS II Manual.
Selecting the Merge Results option will condense down all of the various layers PKS 2 may produce into a single pixel layer as shown below. In this example, an Inkjet 240 Glossy layer group containing two layers has been combined into a single PixelGenius Toolbox Layer. This can provide considerable file size savings but does limit flexibility because the individual layers are combined.