request a 12 month history of your escrow account . . . get your mortgage statement out . . .and then put your tax bills and home owner's insurance policy beside it.
Is the current monthly escrow amount enough to pay the bills? Generally the only reason that a lender changes the escrow amount is that the taxes or insurance have changed and the old amount has left your account short . . .
Imagine if your taxes went up by 100 a month . . . but the lender just kept billing the same amount. Then, eight months later, they realize when they do their once yearly review that your account is short 800 bucks! They will contact you to work out a way to rebuild the 800 reserves (say, add 66 per month for a year) AND add the 100 to the payment so that they are ok going forward.
The lender has no interest in taking more than is necessary for them to be ok long term - the escrow account doesn't benefit them other than to pay your bills :)
The above is correct - the lender usually keeps 2 months worth of taxes and insurance to be able to stay on time, no matter when your payment arrives (or doesnt) and to keep things from going negative instantly if there are changes.