My suggestion would be to contact a local electrical contractor. A 'local' guy may have a contact with the POCO who may be able to assist further then what you indicated.
There are basic questions; time of day the voltage readings were taken, load on POCO distribution grid; historical loads; and...meter calibrations, both yours and the POCOs.
What type of Power Conditioning Equipment do you have? Are you sure that the voltage range you state is beyond the range of your devices?
