I wonder if they were trying to exhibit a realistic tanning pattern.
I highly doubt it. The dolls aren't made one at a time, with parts of each one molded separately. They grab parts from huge lots of medium-skinned limbs, heads, and torsos, then put in the eyes and wig to make her #28. I don't think they spend a lot of time mixing and matching the limbs and head to make sure they're all the exact same shade.
Sunny and Tabby: Monster High Fans and BFFs
My Dolls: Elizabeth Michelle "Liz" Rowland (AGT6), Sebastian Anthony Wilkins (AGT17 Boy), Mary Rose Calloway (AGT28), Claire Bennet (AGT24), Tabitha Yoake "Tabby" Walsh (Jess), Rose Tyler (Julie), and Sonali "Sunny" Matthews
Metroid: Other M is here! MIA until further notice.