Retirement tax questions

@TurboTaxBillMc  Why are some people getting over refunded when the IRS corrects lines 4a and 4b because 4a<4b?  On the other hand why is it working out for some people?  There is definitely confusion with this and line 4a<4b just looks "off".   Due to the IRS combining lines 4a and 4b it's logical that 4a should show the gross distributions of all 1099-Rs.  JMHO