FUTA not calculating correctly

So QBO online payroll completely screwed me. Before I pay a bunch of back 940 taxes I want to make sure I actually owe them as this will trigger big penalties. When filing form 940- using the worksheet (in the instructions) for line 10- ZERO extra tax is due (line 2 is bigger than line 1 on the worksheet) however we have two Corp officers exempt from SUI So they should have to pay the full 6% ? I called the IRS and they said you just do the worksheet and follow the instructions and not do any manual calculations . QuickBooks initially had us liable for the taxes but then did adjustments each year (probably based on the worksheet) saying we didn’t owe money. But it never allowed me to file the 940 . It appears we paid MORE than the max credit towards state SUI even without the Corp officers paying into it. I believe this is because Washington States base wages are very high so we pay a lot of SUI So if the worksheet is right we do not have to pay the extra % towards the Corp officers that were exempt from sui. Yet everyone is stating the 6% FUTA is mandatory for anyone not paying SUI. Why doesn’t the IRS have a new worksheet OR spell it out if the amount paid from all employees covers the a mix credit amount...