Maxbotic I2C sonar. Bad range of readings

Hi all,

I’m using a sonar Maxbotix I2C (MB1242) in my quadcopter. I’m following the steps indicated here:

Everything seems to be ok. The sonar is detected and I get the readings. The problem is that the range (or scale) of the readings is quite strange.
Instead of getting readings in the range [0.2 - 7] meters (or centimeters [20 - 700]), I’m getting values between 327 and 335 approximately. I mean, for a distance of 20cm (or shorter) I get a reading of 327.88. For larger distances, the value varies until a maximum of 335.3. So the distances are being detected properly, however the values returned are in a incorrect scale.

I tried with two different sonars (same model) and I’m getting the same results, so it is not a malfunctioning of the sonar device.
I keep the same parameters as indicated in the link above. Does anyone have the same problem or any idea about what could be happening?

Thank you in advance.