You need to find out if that was actually the reason, or rather one of the other ones listed. Most IRS adjustments are done by computer, which is unlikely to have misread the efiled return data. Call the number on the letter you received for more details.
And keep in mind that TT is only as good as your data entry, and answers to questions. A $1200 refund difference also equates to a $10,000 income reduction at the 12% tax bracket. So also check your data entry for any typos.
