ipad / exchange calendar update process

I have a user with a very strange problem creating a trust issue (not trusting her ipad):

She created a mtg request on a PC (Exchange/Outlook 2007), inviting another person and a shared mtg room. The mtg was scheduled for Monday morning. She got acceptance from both other person and mtg room. The mtg was also on her ipad calendar. On the PC, she rescheduled the mtg for Tues morning, getting acceptance from both the other person and mtg room. She saw the change on her PC calendar.

Tues morning she checks her schedule on her ipad and it shows the meeting Monday. She looks on her PC and it also shows Monday!! She found the mtg room's acceptance of the Tues time in her mailbox, so she knows she actually moved the mtg!

My guess is the ipad didn't see/get the update on Monday, and when it was turned on Tues, it pushed the original time back up to exchange. Shouldn't the last update be kept? Or can the ipad at least be set to be read-only for the calendar sync (not pushing updates back to exchange)?

Thanks in advance.

Keith