User blog comment:Mel3t/lets get one thing straight.../@comment-27141826-20160617181811

The reason why season 2 has more episodes than season 3 is.. since season 2 was the golden age of iCarly and everyone was watching, by the time the episodes were airing, the cast member got a lot of publicity. I don't know where from, but since it became a hit show, the casts were really really busy, and thats why the episodes in the seasons are getting less and less throughout the whole show. (ex: Season 6(7) had really few episodes compared to Season 1 or 2)

And about the DVDs. DVDs are devided as 'volumes' and not seasons, you can guess thats why the seasons are all mixed up.

+ I think in iGot a Hot Room, the characters' ages are 16. In season 5 their 17, in season 6 their 18. Which is also proven by Sam being 18-19 in Sam and Cat, just finishing high school (starting college)