Hello SWOOD, 

I did a search on HOOPP and found this article https://hoopp.com/docs/default-source/members-library/general/hoopp-handbook-en.pdf?sfvrsn=d748c111_10.

Contribution rates As a member of the Plan, you currently contribute 6.9% of your earnings up to the year’s maximum pensionable earnings (YMPE) and 9.2% of your earnings above the YMPE. Whether you are full time or part time, your employer applies these rates to your pensionable earnings expressed on an annualized basis. In other words, they use the pensionable earnings you would have if you worked full-time hours. If you worked less than full-time hours, they prorate your contributions based on the percentage of full-time hours you worked. For example, a part-time employee who has the same hourly pay as a fulltime employee but works half the hours will contribute half as much. Your employer currently contributes $1.26 for every dollar you contribute. HOOPP sets these member and employer contribution rates annually.

It looks like it's a fairly straightforward calculation but where the problem is is the YMPE that it is based on.. 

The YMPE maximums looks like it's based on the average annualized earnings for the past 5 years so it will be different for every employee.. Maintaining in a spreadsheet is probably the only real way to keep track of each employees contributions, I cannot really see any other way.

Regards,

David Crampton