According to Rich Hall's "Sniglets," the phenomenon you describe is known as "Excess Bunnerage."
If the reverse occurs - i.e., your hot dogs come in packs of 10 but the buns come in packs of 8, then you have "Excess Wienerage."
It's a very rare occurrence, but occasionally the number of hot dogs and buns comes out even. This is known as "Frankquilization."
Now you know. And knowing is half the battle!