Modbus read velocity

I've been trying to play with the read frequency of a Modbus sensor with the use of these library functions, and I've found myself with a limitation of 64Hz. If reading two modbus sensors, then the read frequency is limitated to 32.5Hz. Is there a way to improve this limitation? My idea is to have at least 5 sensors that can each be read at a minimum frequency of 100Hz. Thanks!