First, you might want to try to challenge your assessment. Contact your local assessor's office and ask them about the process. If you are successful, your payment will go down by the difference between your current amount and the new amount divided by twelve. (1900/12=$158 per mo. they have to collect now, ex. new assessment 1750/12=$145 per month they have to collect to pay the new bill, savings of $13 per mo.)
This will also change the amount of your escrow shortage. Once your mortgage co. has the new info, have them recalculate the shortage, and spread over three years if necessary.
You may also wish to look into your insurance, if this is also escrowed. Once again, the lower your bills are, the less escrow you have to have to pay them, and the less your shortage will be.
To be optimistic about this, they are giving you an interest free loan of the difference of what they collected (the $600) and what they paid (the $1900 you spoke of).
Once this "loan" is paid back, the amount of the escrow shortage will drop off your payment, and your new payment will better reflect what you have to pay for the bills associated with owning your home, and shouldn't adjust much again unless your taxes or insurance go up drastically again.
Also, if you want to bite the bullet and pay the shortage upfront, your payment will go down to $715 now, though I understand this might be difficult in these times.