From what I can see my state (MD) must be filed the same as what I file federally. If I file (Married-Jointly) using the standard deduction, federally I am refunded but owe for state. If I file using itemized deductions, federally I get back a little less than with standard, but get a considerable refund from MD state. Why is that happening and is that reasonable to happen? And if that is reasonable, should I go back to last year and amend my return to do the same thing since I paid both federal and state last year?
Yes, what you are seeing in your tax return is totally possible. Yes, you may want to go back and look at amending your 2018 tax return for Federal and State.
Maryland will not allow you to take Itemized Deductions on the state if you took the Standard Deduction on the Federal. If your Itemized Deductions are slightly less than the Standard Deduction, that would account for the large change on your Maryland return if you choose to take Itemized Deductions for both Federal and State.
Maryland's Standard Deduction for Married Filing Joint is $12,600 if your Itemized Deductions are even $20,000 your deduction for the state increased by $7,400 by taking Itemized Deductions for Federal and State.
How to Amend Your Return Using TurboTax for a Prior Year