Saturation arithmetic and rounding have area and performance costs. Use only if necessary. For example a Reinterpret block doesn‘t cost any logic. A Convert (cast) block doesn‘t cost any logic if Quantization is set to Truncate and if Overflow is set to Wrap. If the data type requires the use of the Rounding and Saturation options, then pipeline the Convert block with embedded register stages. If you are using a DSP48E1, the rounding can be done within the DSP48E1.