Using the information provided on http://help.arcgis.com/en/sdk/10.0/arcobjects_net/conceptualhelp/index.html#/d/00010000035w000000.htm I've been able to set map levels on my ISymbol objects, but unsure if it's working how I expect. If I'm not in 'Advanced View' (layer properties -> Symbology -> Advanced -> Symbol Levels -> and clicked 'Switch to Advanced View') I don't know for sure if the values are set properly since if I switch from default to advanced the values get reset from 0-N. There seems to be some flag that gets set when you toggle from default to advanced, and I need to set that for my users to be able to know what values were set and/or not accidentally reset the values. Anyone have an idea on what toggles the default/advanced view through ArcObjects? The documentation states default view's join and merge '... are implemented behind the scenes using symbol level objects and interfaces', so there must be a way?