ClimberD can jump in and clear it up if I'm wrong:
Changing a VB in itself wouldnt make the transmission hold more power, just like putting a short throw shifter on a 5MT wont make the clutch any stronger. The 5EAT is still bound by the laws of physics, and since you're not swapping out the clutch packs for the gears, it wont actually make the holding power any stronger. However, the maximum holding power will remain much longer, preserving the life of the clutch packs themselves.