In admin/ManageMembers there's a function jeffsdatediff that calculates the number of days since the current time. It seems to me that you already have a better system for this that understands more units than days. I submitted a pull request replacing with this with just call to htmlTime and removing the function.
Of course if not using relative time maybe people would prefer jeffsdatediff still.
Just a very non-critical suggestion. Take or leave as desired.
Yeah, I think it may be considered redundant.
The main difference is that jeffsdatediff doesn't go to the week/month/year level, it just calculates the number of days, that in the context may or may not be useful, dunno.
ETA: it may be an option (at some point, not necessarily now) to add a parameter to the relative time function to decide what to show "exactly" (i.e. for example limit to number of days instead of years, or number of weeks and so on).