Chapter 5 (v0.5.2) total = 6,693 lines of code.
Chapter 6 (v0.6) total = 7,330 lines of code.
So Ch6 is definitely larger.
Also it's important to note that Ch5 only had 12 animations. Ch6 has 27.
Chapter 5
6,693 code-lines total
708 renders total
12 animations total
Chapter 6
7,330 code-lines total
700 renders total
27 animations total
Also iirc he said the opposite: that CH6 would be slightly larger. Not vice versa. A few months back devs mentioned "restructuring" the game's chapters to better align with a 4-month update schedule. Some updates were massive, with over 1k renders and ~20 animations (which is significant, considering the game's production quality and overall polish). So around 700 renders and 12-20 animations per chapter, with about 1-1.5hrs of story will likely be the standard moving forward for 4mo. updates.
I'll add one more note to this, which is that scriptwriting does take a significant amount of time, and the size of a games script is what extends the avg. person's playtime the most, not the amount of renders. Something could easily be 700 renders and over 3 hours in length story-wise... especially in a game that has branching and varying paths.