Just another random topic that piqued my interest after reading a forum discussion.
This is regarding the delay of each Bain's calling out of ingredients, which can make meth cooking short, or long, based on RNG. For science!

There is an element chance or for easy reference, "CanCook" function being called each time to check if Bain will call out the next ingredient.

CanCook is called the first time, 6 seconds after encountering the dead cooks or when the lab is found (Cook Off).
After cooking, spawn meth after 6 seconds.
After bagging, can CanCook again after 1 second.

CanCook function details

• Base chance is 5%
  
• If check fails, add 10% and call function again in 25 seconds. If successful, Bain will call out ingredient.
  
• After player adds correct ingredient, call function again in 25 seconds and repeat check
  
• On successful cooking each batch, reset back to 5% base chance

So discounting time taken to put ingredient, Bain's voicelines or in-between-batch delays, time taken to cook each bag can vary from 50 seconds to 300 seconds.

Time/chance progression:

Example, with instant ingredients:
0s - 5% fail, +10% (15%) and call in 25s
25s - 15% fail, +10% (25%) and call in 25s
50s - 25% success, place ingredient 1 and call in 25s
75s - 25% fail, +10% (35%) and call in 25s
100s - 35% success, place ingredient 2 and call in 25s
125s - 35% fail, +10% (45%) and call in 25s
150s - 45% fail, +10% (55%) and call in 25s
175s - 55% success, place ingredient 3
After bagging, reset to 5% and repeat function calls

Cook Off is exactly the same except for 3 things:
Base chance is 7%
When function fails, add 15% instead
The delay between each correct ingredient or when function fails, is a random 20 - 25 seconds instead of Rat's fixed 25 seconds.
After some long calculation work, it averages out to 2m16s per bag in Cook Off, just on the cooking delay alone.

So the average time taken for Cook Off will always be faster than Rats.