Maryland Two-income Deduction

Seems like TurboTax is not processing MD two-income marriage deduction correctly.  s/w will only insert the $1200 deduction when the Spouse income is greater than $8200.  At $7000 it eliminates the deduction. Looks like the work sheet is not separating each spouse's wages and takes a percentage of the calculates the joint filers wages.  For example, if wages totaled $7262 TurboTax calculates the deduction as $262 (3.61% of actual wages).  I cannot find income requirements in Md instructions.