Im guessing because deads use your legs / back.
whilst bench is chest / tricep.
therefore my legs and back are stronger?
I use a trap bar if it makes any difference:
(no thats not me)
Finger curls are part of my grip training as when i first started, lifting just 50kg my grip would go first, so doing finger curls with an ez bar and weight, along with weighted thick bar holds, increases my grip strength. allowing me to grip heavier weights.
Also included photo of last fridays workout doing 117.5kg (15kg bar and 51.25kg either side)
Im not doing 32kg on bench now either im doing 37.5kg