Franco,

At some point we will be updating the Plot Scale dialog box, and it would certainly fit to add a checkbox there to control the setting of LTSCALE.
But in the meantime, there's definitely things you can do. We would recommend xref'ing your design file into sheet files, where the LTSCALE can be 1.0. Or even failing that, you could take a blank drawing, set the Land F/X scale, revert the LTSCALE to 1, and then immediately save that file as a DWT Template, to use for any drawing at that scale.

--J