WBS w/o network and activity and cost manual allocation

Dear experts,

my client is currently working on a three level of WBS structures (the second billable) with related network and activities.

The actual cost are retrieven by the timesheet functionalities of CATS.

The new requirement is to move to the following new scenario:

a) semplification of PS structures. Only two level of WBS without the usage of Network and Activities

b) deletion of CATS functionlity with possibility of manual allocation of hours and cost

My question is. Is it possble to manage the scenario a) and if yes which is the way to allocate hours and cost directly on WBS level?

Thanks for any suggestions.

John