If we are looking at the same record then I agree, it says 'to settle on farm', but Im not sure what you mean by "By 1928 he had apparently got a job lined in Snowflake to return to" as the record I attached relating to Snowflake was 1923, and the Ocean Arrivals form is the same year - it even mentions that he arrived on the Montcalm.

The reference to CPR is the Canadian Pacific Railway, who were keen to attract people to farm the prairies. They had a major presence in Winnipeg and almost all immigrants who went on the work on the prairie lands would pass through Winnipeg first, so its possible that Clifford had to register his arrival with CPR in Winnipeg before travelling on to Snowflake.

Perhaps if you go to the Canada boards explain what you know from the passenger records and the Form 30A you may be able to get some more information as to why he would go to Winnipeg first, as appears.