Without knowing which combination of motor and gearbox they are talking about, I can't say. I tend to make my own gear reductions for my Middleweights drive (and will have to for my next big project as I talked about in my build diary). Each motor has its own characteristics and quirks.

For example, the CIM motors I use seem to be fine being overvolted to quite a height with a 6.35:1 single stage reduction drive to the wheels using MOD 1.25 gears. That's fine for the weight it has to shift and for the application it is being used for but I wouldn't dream of using that same combination in a Heavyweight because of the extra weight. I am envisaging having double that reduction in my next project with A28-400 Ampflow motors though that does rather depend on which weight class it ends up being. ^^;

The off the shelf gearbox on Ampflows is 8.3:1 I think, which is relatively high and possibly where that comment comes from if it was paired up with something like a E30-150, which is the "smallest" motor Ampflow make as of writing I think. With the right gearing, that can be used I feel though I must confess, I can't think of any examples right at this moment.