Ah, so the racing world once again has to deal with it's annoying F1 problem. BTW if you expect IMSA to move dates, why not F1 as well?
IMSA works around the WEC schedule as well. GTLM doesn't race at Detroit since it clashes with the Le Mans test day and that's also the last race until July. They're just smart enough to get this crap sorted before they announce it. Not to mention they are giving WEC a much needed mid-season highlight race in Sebring.
But do go on about how IMSA hasn't made any changes to work around WEC.