What is Business Meeting Etiquette in Mexico?

From Kwintessential's "Mexico - Language, Culture, Customs and Etiquette" section are some
business meeting etiquette tips:

• "Business appointments are required and should be made at least 2 weeks in advance. Reconfirm the appointment one week before the meeting.
• Reconfirm the meeting again once you arrive in Mexico and make sure that the secretary of the person you will be meeting knows how to contact you.
• It is important that you arrive on time for meetings, although your Mexican business associates may be up to 30 minutes late.
• Do not appear irritated if this occurs as people often run behind schedule.
• Meetings may be postponed with little advance warning.
• Initial meetings are formal.
• Have all written material available in both English and Spanish.
• Agendas are not common. If they are given, they are not always followed."

This can differ depending what company you are working with in Mexico, can any business travelers share their experiences with the above business meeting etiquette?