I regret that chitubox 1.7 does not keep in memory the change of scale. when you change the scale, after a few manipulations, the increased (or reduced) scale indicates 100% and does not keep in memory the increase or decrease.
Seems to be fixed in v1.8.1 However, I would like to see a global scale setting added in the settings window under the resin properties, so I don't have to change it every build I set up.