Six Delta... I'm sure you realise the climb clearance above the SID has probably been given for expedition... avoids the need to issue two clearances, or maybe at the time there may no need for the standard restriction?
Sorry you feel there is confusion... indeed it seems there is, but as several have said if ever in doubt about your clearance question it... ATCOs have to think carefully about the clearances they give, but a question often highlights an unthought-of abiguity... CRM I think you call it?