I built my coop for 12 max so that's my limit. Currently have 10 birds spanning from 3 to 7 years old. I was adding 4 chicks every other year, but we skipped a cycle due to the fact that we were near capacity at the time (11 birds) plus getting more eggs than we could eat. With laying slowed down and some of the oldest hens unlikely to survive through the winter, I'm hoping to add 3-4 more chicks next spring which will take us to 12 (assuming 1-2 hens pass away).
Since you're already thinking about growing your flock I hope you're thinking ahead on how you're going to handle integration as well. With pre-planning it can be a breeze. Because I am well over the minimum in terms of run space and have a tried-and-true brooder/early integration set up, there hasn't been any real issue with integration. But it's stressful to go in without a plan.
I don't have issues with chicken math though. The thought of being flooded with eggs is enough to deter me.