*Technically* the Android Saga is part of the Cell Saga, if you're dividing Sagas by seasons. (Saiyan, Namek, Frieza, Cell). However, the much shorter story arcs are defined by the characters/villains they focus on. (Saiyan, Namek, Captain Ginyu, Frieza, Garlic Jr., Trunks, Android, and I believe they've termed this one Imperfect Cell.) #17 and #18 are crucial to the Saga regardless.

And of course, you're free to ask me if you have questions. :D