This is true -- most vendors supply a calculator tool that attempts to take this into consideration. Over the past 10yrs or so I've found them to be generally a

This is true -- most vendors supply a calculator tool that attempts to take this into consideration. Over the past 10yrs or so I've found them to be generally accurate, but have noticed a significant deviation in late 2019-2020 from expected vs observed effects. I don't know what method is used but would expect it to be some sort of extrapolation from the average to predict peak rates