Hi Jonathan,
thanks indeed I knew about my old discussion on the mathematical meaning of the scale factor, but I hadn't caught the fact that without the tick the number you set in the box is considered as scale factor (not percentage but fraction) of the real deformation. I was convinced that the only possibility was to set a percentage of the maximum model size and that unticking directly goes to real def.
Anyway it's a bit tricky as when you add the % tick the software switches (without noticing) the reference of the scaling from the real def. to the model size (in perfect creo style! ).
bye bye