I am wondering why Modbus protocol will allow me to write a specific length from a base address but if I attempt to write to the address if the length then It will return an error.

Example:
Action: Write Multiple Register Start Address 2048 (0x0800), Length 20
Result: Write succeeded: Function code:16

Action: Write Multiple Register Start Address 2065 (0x811), Length 9
Result: Write succeeded: Failed to execute Write: Error code:2

Action: Write Multiple Register Start Address 2048 (0x0800), Length 19
Result: Write succeeded: Function code:16

Action: Write Multiple Register Start Address 2065 (0x811), Length 8
Result: Write succeeded: Failed to execute Write: Error code:2