error message shown by rcosdesign filter is not consistent

I think the error message shown for the case number 1 should also be shown for case 2. 1- b = rcosdesign(1/4, 3, 3, 'normal'); Error message is read as "Product of SPS and SPAN must be even. 3 * 3 is not even valued." 2- b = rcosdesign(1/4, 2.5, 3, 'normal');