Assume that the numbers of k-points in each direction are sufficient.
Example - Lengths of lattice vectors: $2\: 2\: 4$
Required k-mesh: $9\times 9\times 5$
Would a $9\times 9\times 9$ k-mesh work? Will it affect the calculation in any way?
Intuitively, I would think it wouldn't affect the calculation because $9$ in the 3rd lattice vector direction is still higher than the required $5$.