Keep in mind that what the current owner is paying for taxes is not necessarily what new buyer would pay. The property will be reassessed. The tax records are your best resource. You may also want to look to see if the current owner is getting any kind of exemptions.
As an agent you probably know that the taxes are what they are, regardless of what a listing agent inputs. Public records are easy to look up and if in doubt, go by the higher of the published taxes, MLS or County records, just to be safe.
It could also be the case that the MLS reflects a Senior exemption that another buyer may not be able to take advantage of. Best of luck.