Hello,
Thank you for your interest in Texas Instruments' power management devices.
The 90degC/W ICthetaJA displayed in WEBENCH® is a measured value taken from the LMR64010 demo board. I will add a message in WEBENCH that notes this to avoid further confusion.
If you have any other questions or concerns, please let me know.
Regards,
Jonathan Arzadon
Applications Engineer
WEBENCH Design Center
Texas Instruments