Recently I bought a "12 cell" laptop battery. It wasn't OEM, but an aftermarket replacement. Clearly marked 8800mah on the pack.
I wanted to get the 12 - 18650 cells to use on a project.
I opened it up and there were only 9 -18650 cells inside, and each cell was only a 2000mah cell. There were 3 dummy tubes inside to take up the extra space.