Concrete Slab Thickness

Need to know the maximum slab thickness that can be screeded with an SXP/S-240/SXP-D? Assume a typical slab on grade application. The maximum thickness is 15″, although we’ve heard of some customers doing more than this. Somero does have 6″ leg extensions currently available for the S-240 and the SXP. The SXP-D hasn’t been designed yet, but can be if needed.