Amex "Pending Charges" Shows $10 Less?

[tpatterson2k9]

Has anyone else noticed that if you look at the pending charges on your online Amex account, the amount shown tends to be $10 less than what is actually billed?  I have had this has happen to me twice now within a two month period, and both times it was because of restaurant bills where I added the tip to the CC charge.  I found this out because each time I tried to PIF on my Amex (including pending charges), my payment was $10 less than the balance due each time.  Has anyone else had any experience with this?  Should I just start paying $10 extra with each payment I make to my Amex card (it's the Blue Cash Everyday card)?

[daylove]

It is common that retailers, especially restaurants authorized the card for the pre-tip amount

[pizzadude]

Also, this is not an AMEX phenoneom, it happens with any CC. Visa, MC, AMEX, Discover, etc.....

[clocktick]

Yes, I write 'CASH' on the tip line and pay the tip, well, in cash.  That way there's no delay, the server gets paid immediately in cash, and I know exactly what the bill was and should be on my cc statement.

*This only works if you carry cash (which I rarely do!).