I re-calculated it and get more results:
Digit Root Symmetric Square
----- --------------------- ------------------------------------------
6 836 698896
12 798644 637832238736
16 64030648 4099923883299904
22 83163115486 6916103777337773016196
26 6360832925898 40460195511188111559106404
28 69800670077028 4872133543202112023453312784
28 98275825201587 9658137819052882509187318569
32 6819209882215742 46501623417708833880771432610564
34 40447213778058769 1635977102407987117897042017795361