Are you asking why you are not offered the option to pay your product fees out of your Federal refund?
Is your Federal refund large enough to pay the product fees, sales taxes (if any), AND the
additional 39.99 service fee for that option (44.99 for California
filers)?
Also, all your Federal forms that you need must be
available for efiling. If you have some that are not yet ready, you
won't have that payment option. You can check here:
https://ttlc.intuit.com/questions/1908854-irs-forms-availability-table-for-turbotax-individual-perso...
Also, in order to get that "pay out of refund" option, you must meet these additional requirements:
You must select to efile the return.
You must choose direct deposit for the refund. You cannot choose a check in the mail.
You must have a USA address.
You must not split the deposit on Form 8888, as you mentioned above.
You
will avoid the 39.99 (or 44.99) service fee if you don't choose that
option, and instead pay upfront with credit/debit card or a prepaid
debit card you can buy in a store.
