Imagawa: Much of the comedy in the original manga was difficult to make into an animated story. The author and sponsor's request was that x amount of plot to take place in the first 12 episodes. The manga was...inconsistent. Parts of the manga involved characters going on a killing spree, finishing up with "Maa, ii ka." / "Oh, well." The audience would have clearly seen through the lie. After episode 12, the anime became completely independent of the manga continuity.
Imagawa: Stills were used for stylistic effect, although the budget certainly played a role. [Laughs.]
Thanks, and Enjoy the site!

Gene Jones