Yes. Because there are a total of 62 available SDI-12 addresses (0 to 9, a to z, A to Z), it would be possible to communicate on the same universal terminal or control port with 62 sensors if each one had a unique address.
In the specifications for the CS650 and the CS655, a limit is stated of 10 sensors per universal terminal or control port because the -VS option gives the sensor an SDI-12 address that matches the last digit of its serial number. That limits the available addresses to 0 to 9, for a total of 10 available addresses. To use addresses a to z or A to Z, change the sensor address with an A200 Sensor to PC Interface or with terminal commands as described in the “SDI-12 Sensor Support” appendix of the CS650/CS655 manual.