yes in call centers you get less than 30 sometimes and sometimes more than 40 hours aweek i don't know how you can put that in Reference letter ,
??? I don't see any reason you can't? And in that case, "at least 30 hours per week" would be a lie, then, wouldn't it?
Any idea? although i think her T4 has 1752 ish hours for year of 2015
So now your friend has "variable hours" which complicates things considerably (since, any week where she works less than 30 hours per week is technically part-time).
She will have her T4 for 2016 soon, and may have all the same information on her final paystub for 2016.
Possibly one way to say it is "The number of hours worked may vary, but on average, she worked 33 hours per week in 2015 (total of 1752 hours), and XX per week in 2016." That could still tip off the VO that some weeks might be part-time, but I do not think would push the issue (too much work already).
BTW - s/he should state pre-tax, not post-tax earnings.