Thanks a lot frag.machine, it worked! I know now where I was making a mistake with my old code.
I forgot, when entity is spawned, to save oldscale, oldmins and oldmaxs. Without them, the mins and maxs value will be set to 0, and, in think function, when multiplied * any value, they will produce only 0;
The clamp check it's also a great thing because it prevents over and down scaling
Many thanks again man!