Hi Jonathan,
Thank You for the update. The note in the datasheet can be used as a guideline for calculation of ICCN as it is not 100 % accurate and is deduced by making some approximations. So the ICCN value should be near enough 272 mA. any value like 290 or 300 should be a good enough ceiling for supply current across a large sample of parts and would be sure not to exceed across the full temperature range for this device as you asked. You can select 300 mA as the ceiling value. or say 290 mA also, as it provides enough buffer to the approx calculation.
I hope this clarifies your query.
Thanks,
Pradipta.
