Exporting UDF and importing multiple times results in inconsitency.

Hi,

There is an issue for US with importing the UDFs into a different environment(OIM), we are creating UDFs in our DEV environment and export it another TEST environment.

Everything is good when we import it for the first time, But if there are any minor changes in the UDF, we change it, export and when 

we import it the second time the OIM console throws errors(Mostly duplicate errors).We do a full export/import.

We thought it would overide the existing UDFs, instead it doesn't overide and throw's filed already existing errors.

Are there any specific procedure to follow or should it be version kind of thing, are we missing something?