Do you book directly thu DCL online or over the phone ? Or do you use a travel agency ? Has anyone booked using the coupons from the Entertainment Books ?

Last time I switched an on-board DCL reservation to Costco, Costco told me that DCL no longer permitted Costco to offer Costco cash cards for taking over a reservation so I didn't get a cash card.We book onboard and name Costco as our ta they give a very generous Costco cash card after sailing.