i'm having the EXACT same problem!
I don't use mobileme, and only use itunes to sync.
my "All contacts" in my iphone4 has 1912 contacts, yet "All from my Mac" only has "1563".
Syncing between my macbook pro address book and phone only displays the 1563 contacts.
I didn't even notice that they weren't all syncing for months until i tried to reupdate my groups I have set up in address book the other day and realised that a couple of new contacts weren't showing up at all.
Sure I could manually enter those I
notice, but where are all the others, and I certainly don't have the time to try figure it out..
I tried opening up a new account on my mac (so I could start fresh without any history or contacts), and went to sync my iphone (i selected merge contacts), which synced fine but again - address book only had the 1500 contacts appear, not the full amount of contracts which are actually on my phone!!!
I have recently made a new group in address book called "recently added", and check in itunes the part where it says "add new contacts to.." (i can't remember exactly what it's called, i can't double check now because im on a work computer which does not have itunes installed), and did a test to see if they update when new contacts are added to address book - and they now do.
but it still doesn't solve my mystery 400 contacts i can't find.
I called Mac tech support, they said hadnt heard of the issue before. my warranty jsut ran out, so for them to open up a docket to look into it, they expected me to resign up for iphone apple care.
this shouldn't be an issue, but it is and it's driving me crazy.
i'd be happy to even be able to export my full contact list so i can copy them in, but that wont work.
help?!?!