Not really the answer to your question, but I would strongly suggest you change the architecture of your list where you don't have "Time" as part of the member. Instead, use a module dimensionalized by time for the time data which in turn allows you only use the "non time" member once. For more information about this, please check out this best practice article.
Don't think you would get a concrete answer on this one. How would you like to convert weeks to Months? Month value should represent calendar month or month value that you would see in a typical weekly calendar?
If you can't change the source data one idea would be to enable a weekly calendar in your model to load the data in, but not sure how this would impact the rest of the model.
Also to give a bit of an insight into this type of conversion I would suggest you take a look at this answer given by @JaredDolich :