Measuring audio transformer impedance with LCR meter

I'm just trying to figure out how to use my fancy LCR meter. All I want to do is measure the impedance of a 1:1 audio transformer and compare against the data sheet.

Data sheet says impedance should be 15K with a 600 ohm load but the LCR is spitting out 3.2k. I have bought the handheld DE-5000 to verify the first LCR but ability meters agree.

All I have to do is hook a 600ohm load up to the secondary, right? I'm totally confused
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"If I have a transformer whose turns ratio is 1:1 , and I connect a 600 ohm resistor across the secondary , in this condition what is the impedance looking into the primary?"

If I had any engineer friends I probably would have asked them in the first place. None the less, I'm guessing due to impedance reflection, the 1:1 ratio and a 600 ohm resistor across the secondary the primary impedance would be about 600 ohm? If that is the case, why did the Datasheet say 15K?