If your QuickBooks® company file is configured to enable sales tax, be sure to check the box "Company file is configured to use Sales Tax". This ensures the Sales Tax is passed into the exported file.
In QBD, if this flag is set, ClubExpress will send an AUTOSTAX line with each user transaction, even the ones where sales tax is not applied (membership signup and renewal, event registration, donation, etc.) Where sales tax is applied (storefront transactions), the AUTOSTAX line will contain the sales tax amount.
If this flag is not set, sales tax is exported as a transaction line item, with the actual sales tax account specified in the split of funds.