Change units , and respect the scale of the scene? i got this bad idea to set up my blender in meters
and when i draw architectural plan , everyone use cm 
so then i tried to change my units 

right now its like that :



my guy is 1.7meters tall , so its 170cm when you convert .
if i want to move an object 30cm to the left i must type 0.3 
and i really dont like that , no architects does that, its just not how you draw arch.

so here the changed version



now when i want to move something 30cm to the left i need to type 30 , thats exactly what i want , but now my object is 1.7 cm , all my scene is screwed 

wait i know , i know, i can scale it afterward...
but then what about my 130+ assets and +300 materials that are made in meters? are they all to rework one by one ?? i think its a huge fail blender think that 1.7 in meters is 1.7 is centimeters ... 

can someone resolve my problem ?
thanks
When you change the unit preset to centimetres you are changing the unit scale. The unit scale determines how big a unit is, a scale of 1.0 means one unit is one metre, and a scale of 0.01 means the same one unit is 0.01 metre or one centimetre.



You don't need to change the unit scale to be able to enter centimetre measurements, you just need the object size to be the correct scale compared to other object in your scene, this would mean scaling down small objects that import too large or adding .0 before any measurements you want to be in centimetres.

To move an item using unit measurements, press = to start advanced entry mode before you enter the amount. That is GX=30CM will move the object 30 centimetres on the x axis.