The number of output variables (VAR_OUTPUT) should be within a limited range set by your organization. Refer to your coding style guides.
Using a function block with too many pins affects readability (a limit could be around 10 for graphical programming languages).
If more input, output, or input/output variables are required, consider reducing the number of pins (input, output, input/output variables) of POUs by introducing a structure to group some input, output, or input/output variables.