I have a variety of these and other brands boxes. For those I can turn bullet up I have added a piece of soft foam snuggly fitted between the lid and bullets to help stop the rattling, aka moving around.
You could cut some soft foam to fit to inside each slot/hole to stop the rounds from moving around in your current box(es). But the rim will just pull the foam out when you pull the cartridge out because thebrim is wider than the brass.
OR
Another alternative would be going up in caliber then line with foam to keep the rounds from rattling, aka moving around.
As I first stated I own a variety of these boxes: Plano, MTM, Frankford Arsenal, and a couple of others. Other than Name brand, style, caliber and cost, they are all pretty much the same.
I've read others opinions on which way and why to place bullets down or up and after more than a couple of decades using these boxes: factory ammo has never been a problem. Reloaded ammo that's a different story. A No crimp, Non crimp, improperly crimp, bullet will come loose. However, a properly seated, crimped or non crimp reloaded bullet like a factory bullet will not come loose. Currently I have straight wall and bottle neck ammo that I reloaded 4, 5, 6, years ago in these boxes bullet down that are still solid.
If your worried about the airlines, which is why, just place a piece of soft foam between the lid and cartridges to minimize the sound of loose cartridges in your ammo box.
I'll be watching this thread for:
discussions on up or down in these boxes,
if anyone does make a reasonably price 50 and 100 count boxes.