With regard to your post, you picked out a easily found and relatively cheap and common caliber. Most of my loads are for not so easily found stuff like the 10mm, 41mag, Ackley Improved calibers, and even the common stuff for my rifles like the 25-06 and .280 are still as high or higher than say the .270 and 30-06 and aren't generally as easily found in more than one weight on the shelf.
I shoot quite a lot, maybe not as much as some but more than others. I look for sales, groups purchases withing my local area, and anything else to help offset cost. Like many others, I try and purchase in bulk to offset the other cost for quite some time. I spent hours looking over loads, and cost per round to decide which might be the cheaper load for my particular needs.
While the savings might not be much per round if purchased like your figuring, the fact that when I do load even as small a number as 10 rounds for any of my arms, I get the same performance from them as I did from the previous amount, with out having to worry about this or that lot being faster or slower. When I DO have to change things up, the loads and components I have chosen for my stuff are such that there is hardly if any differences between one lot to the next.
This to me, is well worth the added savings, no matter how small, over simply going to any ol shop and picking up a box of 20 or 50 factory loaded rounds, than having to adjust my scope or sights due to the new box being different form the last.