@tde , if you cannot see the actual form ( and therefore confirm that the line 13 is in error ) , you can :
(a) write to the IRS to explain what took place -- that it is an error of putting the amount on the wrong line but the total amount of refund expected is still correct --- on the form they sent you there is an area to disagree with them and explain why -- that is where you put your explanation
(b) Prepare an amended 1040 on TurboTax and send this along with the answer to IRS query.
My pref and strong suggestion is to follow option (a) since IRS is already asking for explanation. You should be getting a resolution soon thereafter.
Good Luck
