why do i see different netflix films on my imac than I do on my ipad

For a while I have been right royally confused.

During the day I've had a look around on Netflix and added a film to the 'my list' section of netflix using my imac...or sometimes started watching something.

Then, because I have my ipad set up and linked to our large screen tv upstairs, in the evening I switch on the ipad access netflix and try and find the film I've added during the day whilst I was on my imac.

Can't be found.

This has now happened a few times.

I brought my ipad downstairs and side by side with my imac did a comparison of films listed, both generally under different headings on netflix and also on the 'my list' section. All totally different. Films that are available on the imac netflix can't be found on the ipad and vice versa.

Why is this? If anyone knows the answer and a possible fix/solution I would be most grateful.