I think the shorter runs mess with my head a bit. My body wants to slow down around the 80 second mark and it's only once I get to run #4 or #5 that I really start getting into the groove of things.
From my memories of the last time I did C25K, I remember enjoying the longer runs more.
But in the meantime, I'm focusing on form and a slow but consistent speed. Building up endurance!
Happy running