I have spent [way too much] time trying to figure out Hoover's model numbers, including telephone calls to the American central lines, where operators know little ... but it seems there's no Canadian headquarters, at least with a current street address or phone number. [Merchants or salespeople almost never know this type of thing.]
The likeliest correct answer to your question is general in nature: '900' and '950' seem to distinguish the different Canadian and American marketplaces, whatever the first four numbers may be.
Interestingly, many items numbered this way are no longer available - Hoover discontinued them in favour of a 'Platinum' series, (commonly reported as less well-made than the earlier models).