How do I get the full deduction for Louisiana START contributions for MFJ? TurboTax limits to $2400 per beneficiary when it's really $4800 per beneficiary for MFJ.

Louisiana's START (529) website and annual deposits statement clearly state that deposits are deductible from LA taxable income up to $4800 per beneficiary for joint filers.  TurboTax won't let me deduct more than $2400 per beneficiary which is the single filer limit.