Solved
Last year it was listed as an Adjustment. This year it does not give an option of "Contributing to a 529"
Looking at the entry screens using TurboTax Online, there is a page titled 'National Guard Pay and Prepaid Tuition'. Select 'yes' next to the prepaid tuition question. This will take you to the page where you can enter the amounts contributed to the MPACT or MACS programs in Mississippi. If both you and a spouse are listed on the page, enter the contributions made by either or both of you to one of these programs.
(My assumption is that the screen will be similar if using a CD/downloaded version of TurboTax, but I did not check it specifically.)
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