You can see this in the image below. I have deliberately changed Pen #2 to 0.70mm to demonstrate the change.
My line weight table in my template has Pen #1 set to 0.10mm and Pen #2 is set to 0.15mm. They are very close in weight so I never actually noticed this in ceilings.
Whilst I don't see the need to immediately change my template, it is certainly interesting.
If you didn't already know, all hatch patterns in model object surface & cut patterns default to Pen #1. You cannot change this, it is hard coded into Revit. So, I have always left Pen #1 alone and started my pen weights at Pen #2. However, now learning that ceiling patterns are also hard coded, perhaps it is better to start your pen weights at Pen #3?? Hmmmm...