VA IRRRLs are unique when it comes to VA loan entitlement. Getting an IRRRL does not require the use of a new or additional entitlement. Whatever amount of VA loan entitlement was used to secure the original purchase loan remains the same for the new loan, regardless of the loan amount.
Having a higher or lower loan amount on the IRRRL can affect the guaranty amount, which reflects how much lenders would recoup in the event of default. But it cannot affect the amount of a Veteran’s previously used entitlement.