Chumley,
You are right when it comes to the length. At work we have digital camera that needed batteries. I plopped in the ROV cells and it didn't work. After some significant hair loss and 40 minutes later, yes they are shorter, but you can barely see it. Easiest way to check, place two identical cells beside each other on a hard flat surface, and put the cell in question next to them. Hold a ruler across the tops and see if there is any difference. The eyeball will see it.
Always have had great performance with ROV's, but I still buy in bulk based on price.