How to Make Money With Amazon's FBA Fee

In December of last year, I got an alert which I never acted on where the dimensions was 14 by 4 by 4 and it changed it to this 15 by 11 or 12 actually by 4. So I'm like, whoa, that is crazy. How much more am I paying because of this? And sure enough, look at what happened all the way back in December guys. The FBA fee went down to $5.69. Now how much does that mean? Let me just say it's a $3 or $4 different.