Prompt to remove hours from the end of the project when manually allocating hours

When the type of work is "fixed work" (we have X hours assigned by our customer) the point is how to spread and allocate them differently in the different days.
This depends on the constraint of not assigning more than 8h a day for each resource (which doesn't seem to be taken into account by Clarizen) and by other 2, 3 or sometimes 4 other projects that the resource has in parallel.

So when the hours are allocated automatically, I can move some of them around manually, and Clarizen will automatically decrease the hours from the end of the project.
Example: let's say I allocate 4 hours a day for 10 days. Then for some reason 2 days in the middle of the project the resource can/should work 8 hours instead; I set the hours for those 2 days manually, and Clarizen automatically removes 8 hours at the end of the project (i.e., the project will end 2 days earlier, which is the expected behaviour).

As soon as all hours are booked manually, instead, doing the same thing will produce an error in Clarizen saying that we cannot allocate more hours on the project.
Of course we don't want to allocate more hours, but then we have to MANUALLY decrease some hours at the end and then manually play around with numbers and make the figures match. 
That's dreadful. It goes without saying how frustrating this is when we have to make figures match for resources that are allocated a different amount of hours for each day of the week.

Expected behaviour: similarly to the automated case. Maybe it might produce a warning saying that the amount of hours are exceeded so it will decrease the hours at the end of the project (where the user can accept Yes or No).