I think the tattos are the same.That is because Zell is Ultiīs grandson.

That is the tattoo of the SeeD (SorcErEss Dinasty).

SeeD heritage is as follows:

Seifer et Almasie (Seifer D'Almasy) marries Ultimedea and gives birth to Ellone Rinva.
Ellone Rinva marries Sqvall giving birth to Zell
Zell marries Qvistix giving birth to Sophie
Sophie marries Irvine.

This 8 persons form SeeD.
This is a codename given by the Gardenīspecial students but no one knows its real meaning.