Why is 'applicable percentage' always reverted to zero no matter what I enter

[happydad88]

Under Biz Income and expenses (Home and Biz turbotax), why is 'applicable percentage' always reverted to zero no matter what I enter?  The percentage for SSTB operating income takes what I entered, but not the 'applicable percentage' input box before SSTB.

Thanks for any help in advance.