As per the current functionality, The Time Off in Lieu is posting the overtime into number of hours and you would like to know if there any possibility to convert number of hours into days and then post into employee's Time account instead of hours?
SuccessFactors - Employee Central Time Sheet
Currently there is no possibility to convert to days as the unit for Time Account Type for TOIL must be in 'hours'.
Please refer to the section Configure Overtime Compensation for Employees including 'Time Off in Lieu'
Time Sheet Time off in lieu TOIL Time Account Type Unit Overtime , KBA , LOD-SF-EC-TMS , Time Sheet , How To