Is there a Microstation variable that matches the IPLOT:
IPLOTSRV_USE_POST_STROKE_LINE_STYLES=TRUE
When IPLOTSRV_USE_POST_STROKE_LINE_STYLES is set to true, IPLOT retains the MicroStation custom line style but applies the color/style specified in the design script to the strokes that make up the custom line style. When set to "false", the design script removes the custom line style from the element and outputs the element with the color/style indicated by the design script. The default is “false”.
Yes The Microstation variable is
MS_PLT_DESIGN_SCRIPT_USE_POST_STROKE_LINE_STYLES
it needs to be added to your user or project .cfg file and set to a value of 1.