TLV9301: MSL Ratings of SOT-23 (DBV) and SC70 (DCK)

Why does the SC70 (DCK) package have an MSL rating of 2, while the larger SOT-23 (DBV) package has a rating of 1?  I assume the chip is identical inside of the package, so it must have to do with the packaging.  But why are there many other Texas Instruments op-amps in a SC70 package that are rated MSL 1?

Thanks!

Regards,

Greg