If I print a dgn in which there are models, sheets and drawngs using my pen table (*.tbl), the models are printed as expected, but the sheets or drawings have the same thickness
1) Go the drawing and open the reference tool
2) In Visible Edges column, change from Dynamic to Cached (this automatically change the correspondent sheet Visible Edges setting)
3) Make the same for all your drawings
4) Print using the pen table as usual