There seems to be an issue with the 'location' of the blur centre not being in relation to where you placed it...
Here's my scenario.
Made a smart object of a road.
Added a radial blur (zoom) with the 'blur centre' as indicated in the gridded window, halfway down and 1 thrid from the left and set the zoom to 20.
Looks good.

Open a similar image and do the same except for the 'radial centre' has to be top left for this image.
Back to the first image, I have to adjust the zoom amount.
Click the radial blur element in the layers panel (under the smart object) to adjust the amount.
The 'blur centre' is now indicating the 'last used' location.

This is quite annoying, especially when these images have to have a very definate blur centre location. - I would like to see some kind of x and y location to the blur centre even if it's something I could just write down or add to the layer name.