TAX RATE AREA INVALID ERROR

Hi All ,

IN P4008  , TAX/RATE area is already set up w e f 01/01/2018 .

but i am entering order for current year where invoice date is 22/12/2017 .

but at the time of sales update , it gives tax rate area invalid error .

if I change the effective date to 22/12/2017 , then it works .

which shouldnt be the case because taxes are applicable only w e f 01/01/2018 .

in customer master tax rate area is already assigned .

does it mean that , I have to update customer masters only just before start punching the orders for 01.01.2018 ?

kindly advise

Thank You