On the 28th of November 2017, General Department of Taxation issued official letter no. 5475/TCT-CS as guidance for expense recognition of deductible VAT on purchase.
In case input VAT of a tax period qualifies for VAT declaration, it can be declared and offset against VAT payable in that period.
In case deductible VAT is recognised as expense, there’s no regulations that it can be treated as deductible expense for CIT purpose.