I'm wondering with regards to how the meaning of {weS} is altered, when the suffix {-chu'} is added.

Suppose we write:

{Huch wIweSpu'}

we've suffered a reduction of money 

But how is that any different from: 

{Huch wIweSchu'pu'}

we've perfectly undergone a reduction of money 

Does the {Huch wIweSpu'} mean that we've lost some money, while the {Huch wIweSchu'pu'} means that we've lost all our money ?

I'd say so. Mind you, the lack of -chu' on the first one doesn't mean it can't be all your money, just that you're not specifying how much money is lost.

But even so..

If we write:

{100 *dollar*mey DIweSpu'}

we've suffered a reduction of 100 dollars 

How is it any different from:

{100 *dollar*mey DIweSchu'pu'}

we've perfectly undergone a reduction of 100 dollars 

In both cases, haven't we lost *exactly* the same amount ?

In this case, you'd have to find some other meaning for the -chu'. I don't think you can divine its meaning here without further context. The meaning of any -chu' is very dependent on its context.

-- 
SuStel
http://trimboli.name