Sorry I don't know. Most of the adjusted questions are about reduced refunds, not getting more. I think you will get it the same way. Looks like you get more. Did you leave off a dependent or have a new baby?
1400 is the Stimulus payment for each person. You might have entered the wrong amount for the 3rd Stimulus payment and had a low amount on line 30 for the Recovery Rebate Credit.
The 750 could be for anything. Maybe the Child Tax Credit on line 28?
