==COUPDAYSNC(settlement, maturity, frequency, [basis])
=COUPDAYSNC(DATE(2019,2,15),DATE(2024,1,1),2,0) returns the same result as =COUPDAYSNC(C6,C7,C10,C11)
=COUPDAYSNC(C6,C7,C10,C11) uses hardcoded values for the maturity date, settlement date, and frequency.
=COUPDAYSNC(C6,C7,C10,C11) returns #VALUE! if settlement or maturity dates are not valid.
=COUPDAYSNC(C6,C7,C10,C11) returns #NUM! if maturity date is not later than settlement date.
The COUPDAYSNC function returns the number of days between the settlement date and the next coupon date, based on three required arguments.