Can I put in my interest mortgage with out it automatically changing to a different amount?

If you are filing with TurboTax online, let's do these steps: 

• Check your internet connection.  Try to log out and sign back in the program. 
• Clear your cache and sign back into the program.  To clear cache, click here: Cache
• You may also try a different browser.  
• Then try to re enter the entry. 

Note that your mortgage interest might not change your total tax refund.  It will only change if your total itemized deductions including the mortgage interest exceeds your standard deduction.  In the TurboTax program, when you enter itemized deductions such as mortgage interest, property taxes, medical expenses, charitable contributions, all of these items are added together. Unless the total of itemized deductions exceeds the standard deduction for your filing status, you would not see any change in tax due or refund.