One reason I won't/don't try and figger my cost vs factory is pricing components. I bought some powder several years ago, price? I bought some lead18 years ago, price? Bought some primers 20 years ago, in bulk, on sale, how much did they cost? Do I research current component pricing vs factory ammo? I use a lot of range pick ups and "once fired" brass. To be fair I would have to include shipping (if I bought ammo on line), wear and tear and fuel for buying locally (only one place in my small town to buy components so I occasionally have to/like to drive 50 miles north) and of course HazMat if I order components on line. Waaaay to much trouble just to satisfy my curiosity.
The main reason I don't try to place a dollar value on my handloads is I like reloading and adding a "money factor" might ruin my pleasurable pastime. So, bottom line; I reload because I like to reload!