This post gives us an estimate for what percentage of the iPhones are getting throttled by this issue. I think it's reasonable to use this as a proxy to estimate how many units were at risk of shutting down and it is the minority of units. Happily it appears both of your devices are in the majority of units which don't exhibit this issue.

https://www.geekbench.com/blog/2017/12/iphone-performance-an...