please explain the exp hybrid penilty

[iRFNA]

but if you've got like 3 slivers of a cherry pie but i've got like half of a pumpkin pie the pumpkin pie weighs more but it's smaller around right so the cherry pie is a halfling and th epumpkin pie is me i think one of those huge pumpkin pie pieces would be more filling than the halfling even if the pupmkin pie is asmaller