My old notes say the following:

A one-unit change in X1 is associated with a (eB1 – 1) * 100percentagechange in Y,

this is approximately equal to 100(B1): If, -0.1 < β1 < 0.1, 0.1 is a rule of thumb.

So if I am correct, which seem to be quite a bit off from -250, I believe the *100 is a generalization, then for a ratio change of 1 you would have a -92% change in Y. Now the next question is, that I think Y is now on the geometric mean scale so, perhaps the results is:

For a 1 unit change in X1, you would expect a 92% decrease in the median of Y. Whew, not as clear as we usually think if I did that right.