Thats weird as my check out page does not do that. It has regular retail, with just a $30 coupon applied at the bottom of the confirmation, not deducting $ from either shoe specifically.
This won't work, since on my confirmation page (and not the receipt) it takes off a portion of the price for both shoes.
I think my $25 kids Croc was listed as a $14.97 shoe.
If you return one pair, you will only get a portion of the shoe price back (the portion of the price that you paid).