VMAX3 drives number

When I make XML using vmax sizer, I saw one warning.

Supplied drive (2.5" 1.92TB Flash Drive) count does not satisfy the performance best practice of balancing drives across engines. The drive count must be a factor of 16 , for making this a balanced flash configuration.

This VMAX is RAID5(3+1) two engine. so I think if vmax can be configured 16, 24, 32 ... drives

But i have to configure it with 16, 32, 48 ... drives to remove that warning.

Could i know why? And is there any problem if I ignore that error?

thanks