It's more precise, not more accurate.
Precision is about how small the smallest demarcated units of measurement on a scale are. In another word, it means "fineness."
Accuracy is about how true to actual weight a scale reads. In another word, it means "correctness."
A scale can be quite precise (e.g. allows you to read weight down to a milligram), yet wildly inaccurate (i.e. simply gives you the wrong weight). Accuracy is usually more important than precision...and the units of measurement used have nothing to do with accuracy.
In the OP's case, unless it is a damned fine instrument that you can't bear to part with, it should go back for having been sold with a false description of the weight.