Home office miscalculation

I found an error in my calculation on form 8829.  When I use the Simplified Method Smart Worksheet, the factor in Line E had shown only $750, versus $75,000.  At $750, I owe about $23,000 more in taxes after paying & $17,560 in quarterlies.  When I re-did the calculation at $75,000, it erases my taxes due and gives me a refund of about $2,800.  I just want to make sure my calculation is correct before filing, as this would be a huge mistake.  Any advice out there?

 

Thanks.