Why do the etailers and retailers get different wave numbers on their cases anyway--I've noticed this with basic figure and titanium ship cases..the numbers are vastly different from etailers boxes from retailers boxes. 
Because the majority of the etailers call the Waves by the order they were released:
Wave 1 - Carkoon
Wave 2 - Hoth
Wave 3 - Geonosis
Wave 4 - Coruscant
Wave 5 - Tatooine
Wave 6 - Endor/Jedi
Wave 7 - Endor/Naboo/Tatooine
Wave 8 - Final 22, #53-62
Wave 9 - Final 22, #63-69
Wave 10 - Wal-Mart Exclusives #70-74
For some reason, Hasbro called the Geonosis wave
Wave 2.5 on the boxes they sent to the retailers. That screwed up the numbering making the case numbers off by 1...
Wave 1 - Carkoon
Wave 2 - Hoth
Wave 2.5 - Geonosis
Wave 3 - Coruscant
Wave 4 - Tatooine
Wave 5 - Endor/Jedi
Wave 6 - Endor/Naboo/Tatooine
Wave 7 - Final 22, #53-62
Wave 8 - Final 22, #63-69
Wave 9 - Wal-Mart Exclusives #70-74
It all comes down to Hasbro doing whatever it wants on the case numbers and the etailers just trying to find a way to help the average joe out by using a set of numbers that is easier to follow.