Same thermistor model (103) with varying response
The allowable variation in the thermistor characteristics should be defined in the component datasheet. If the parts you purchased are not meeting the datasheet limits then you should return them to the supplier.

There is no solution that will make all thermistors of a given type "accurate", because there will always be variation in the components. If you want to limit the variability then you must make this part of your purchasing agreement. The other solution is to perform a final calibration procedure to determine the unique correction needed for each unit, and store the correction parameters in some kind of non-volatile memory.