Mexico - Mexicana checkin time

Mexicana website requests checkin 3 hours prior to departure (international flight from SFO). Is that really necessary? Does anyone have experience with the baggage cutoff times?

I know they are understaffed in Cancun, but no experience at SFO.

You can look for other threads in this forum regarding problems for not allowing enough time for chek-in with Mexicana. As far as I remember, they talk about CUN and MEX. I would be cautious, however. It is a known fact Mexicana has important problems with its land personel and work.