Sizes of font changing on different machines

It seems that the fonts and font sizes change during production ..
... when sharing SL2 file across 2 machines.  Both running W7 and the same SL v2_10.

This is really bugging me now because every time I open any of these files on the "other" machine, different sections of text have changed and have to be re-edited.  I am finding it very difficult to work collaboratively with other colleagues as we are creating rework for ourselves each time we open up the course.

I've seen your comments regarding checking the DPI of the machines, and I can assure you that they are all the same.

Please can you get back to me on this issue as soon as possible. This is slowing down my progress with production significantly.

Thanks,

Alex