TPG gets your refund when you request that Turbotax fees be deducted from the refund. they deduct the fees and then if you're set up for direct deposit electronically transfer the remainder of the refund. $18 seems sort of small so it may be that the IRS changed your return. it may take up to 8 weeks for you to receive an explanation from them.
don't bother contacting Turbotax, once your return is accepted they get no further info. search the internet for TPG contact info.
