40% is a ballpark estimate, maybe it's 35%. Do the math yourself.
Apple's fiscal quarters are all exactly 13 weeks long (ending on the last Saturday of the period) with the rare 14 week quarter. Right now, it looks like Apple will be realistically four weeks late with the iPhone which is 30% of the number of selling days.
It is unrealistic to assume that Apple will have unusually high amounts of inventory. All of these companies are struggling with availability. Look at Nvidia's GeForce 30-series launch. Absolute disaster with both 3080 and 3090 cards selling out immediately. The Xbox and PS5 pre-sales were almost as bad.
Silicon foundries can't pump out the chips fast enough and it's about to get worse. AMD announces their upcoming CPUs and GPUs this month. Apple and AMD (the latter is providing SoCs for both new game consoles) have locked up TSMC's schedule into the first part of 2021 already. Apple has yet to announce the iPhone and Apple Silicon Mac.
With the release of two new game console platforms, there is an abnormally high demand for premium silicon in a year that supply will also be constrained by COVID-19.
If I were a financial analyst, I would not highball Apple's numbers this year. There are way too many factors outside of Apple's control.