You may have that confused with the 12-night or longer cruise/cruisetour, yu receive 2 cruise credits. This is listed right in the Crown & anchor socity member benefits in the magazine. I checked the magazine, and didn't see anything about booking a jr. suite and getting 2 cruise credits, but I may be wrong.
NCL Dawn (Repo 14 nite) 11-1-09
RCCL Mariner of the Sea (Mexican Riviera) 4-18-10
NEW: Receive an extra cruise credit when you purchase and sail in a suite (categories RS, OS, FS, GS, JS) for sailings beginning on or after January 1, 2004
Receive two cruise credits for a 12-night cruise/cruisetour or longer on or after January 1, 2003 ''
2/13/09 Carnival Paradise
2/22/09 Freedom of the Seas
83/Azure Seas; 84/Song of America; 88/Stardancer; 92/Jubilee; 96/Viking Serenade; 97/Holiday; 99/Enchantment OT Seas; 00/Elation; 01,02,02,03/Ecstasy; 02/Voyager OT Seas; 03/Victory; 04/Adventure OT Seas; 05/Sapphire Princess 05,05,05,06,07/Monarch OT Seas; 06,07,08,08/Paradise; 06/Freedom OT Seas; 07 Pride; 07 Pearl; 08/Valor; 08/Serenade OT Seas; 08/Coral Princess