what item are you talking about? Weapon or eidolon? considering amount of events devs pumping out, its more efficient to limit break items rather than stack copies of them, but if you can get multiple full limit broken weapons, then go for it: you can put multiple copies of them in your grid and they will both contribute to your stats. Same goes for eidolons.
I'm sure you guys have just been wondering where I am and what's going on....
I finally got it figured out. However I just couldn't get it to work with Van Helsing Or Other suggestions, and I think after a few more levels on my weaps, I was dealing enough damage.
Also, I just got Andromeda and I'm working on lvling her up as quickly as possible.
Now as I'm further lvling my weaps and eids, I'm almost getting to strong and am running into the problem of getting to Medusa too fast. Sometimes I'll get to her with 2or 3 turns remaining for Amons skill to cool down and be usable again. Sometimes my main char is 3 or 4 attacks away from being able to burst. However I have been doing steady Expert for the past couple/few days. I've even managed to pick up 2 Plat chests and each time it had the SR Dark Hammer, so now I'm 1 away from full LB on it. I've got 2 Medusa, and 2 SSR Glaive, and 1 of the other Weaps. Just picked up 9 of the SP so I could get Andromeda. Anyways thanks for you help and suggestions. I like looking around here and seeing what I can pick up from you guys.
I am seeing this happen in Ultimate as well. Getting through the trash mobs faster makes the boss more difficult. Not just building up TP, but getting eidolons and skills ready. I have taken to risking some status ailments in the beginning to reduce my time on Medusa herself.