Is there a logical reason for this? Or is it just one of life’s mysteries?
Cecil has spoken, but still did not really answer the question. Put in a lot of opinion, but well Cecil opinions may be facts? 
http://www.straightdope.com/classics/a2_350.html
Must be one of life’s mysteries as you have said.
Listen to your Unca Cecil, for he is wise in these matters.
That is some impressive triple simulpost!
If only it were as the OP posits. 12 dogs and 8 buns would at least allow for 2 packs of dogs = 3 packs of buns. A volume easily consumed by a busy family before the buns went stale.
However, I most often see 10 dogs and either 6 or 8 buns. That would take some massive buying to even out. 
One of my favorite Steve Martin bits from Father of the Bride involves this very same question.
When I buy hot dogs I always buy packages of 12 buns (not sure whether I can even buy a package of 8 in my local Safeway; I’ll have to pay attention the next time I go). I guess we’re more logical in The Great White North.
Just picked up a package of Hebrew National hot dogs. Seven in the package. (12 oz.)
http://www.thomasjlang.com/archives/000548.html
http://www.nwherald.com/MainSection/local/340455405038463.php
Rejoice, and waste bread no more.
It gets worse. A store by us sells hotdogs in a pack of 8. Guess how many buns come in a package in the next aisle?
Cecil never fails to impress even when He can only offer hypothetical reasoning. I have never read that particular column; I thank you all for linking it not once, not twice, but THRICE. 
So, there are 10 hot dogs per package rather than 12. I’ve never purchased hot dogs or buns since I don’t eat hot dogs. A friend asked me this question so I was essentially asking on his behalf though I was curious myself. I could have sworn he said “hot dogs in packages of twelve” but of course humans are vulnerable to miscounting.
Only if you are poor at math. 2 packs of 10 dogs, two packs of 6 buns and one pack of 8 buns.
I’ve always been under the impression that the end pieces of a bread loaf make up the two missing rolls?
I solve this problem in one of two ways. Either we buy bun length hot dogs in the first place, which come 8 to a package, or I make beanie weenies from the two leftover dogs in a 10 pack. My husband LOVES beanie weenies, and I like them well enough to eat them on occasion.
Hot dog buns, by the way, make pretty good garlic/herb bread, are good for other kinds of sandwiches (tuna salad, for instance), and make pretty good stuffing base, much better than the regular white loaf bread.
Hey now! You can’t mix types of bun bags because the buns won’t be the same.
–gigi, OK at math, even better at compulsion
An odd number?? ::head explodes
Ya buncha woosies. You don’t need a bun to eat a hot dog. A hot dog should be shoved onto the end of a long stick and stuck into a roaring fire until black. Then you eat it off the stick.
Problem solved.
The 10/12 dogs/buns ratio is well answered.
You always need an extra bun.
When one rips coming out of the bag, you need a “spare.”
One bun gets crushed in the massive bags of groceries on the way home, you need a “spare.”
When the kid at the table spills his juice, and it soggifies the bun, you need a “spare.”
Think of the sausages! One of those needs a bun, you need a “spare.”
The stoned teen shows up, eats a bun sans dog, while waiting for one to cook, you need a “spare.”
That guy that wanted it toasted, passed out and forgot to take his bun off the grill, you need a “spare.”
If you use one as a spare from an 8/8 purchase, do you really want to be that guy (or gal) that has to eat their hotdog cut up, with a fork? (Honey’s camping adventure excluded… then who needs buns at all!!! )
I like Hormel Wranglers Beef Franks, they come 8 to a pack. And I get Mrs. Bairds hot dog buns, also 8 to a pack.
But it’s usually more hot dogs than buns. In my case, I enjoy the “spare” dog; if I’m famished and am waiting for the four dogs to cook, I can eat that fifth one raw and cold, and still have four buns left. [10 dogs {one brand by me is packed in two 5-dog sections}, 8 buns scenario]