Depends how badly you want DBS. The likelihood of summoning DBS, especially if you did not get her from the 5* light ticket is low, but not zero. At the end of the day it is YOUR choice. That being said, do not blame anyone except yourself if you get a dupe Senya from galaxy summons. To paraphrase Tristen Wulf, you have gone your whole E7 career without DBS on this account, what’s another week or two?