We'd definitely need more information, screenshot and blue print of the module would help, but to answer in general terms.
> [EASY] Copy Across/Copy Down: Requires Cost Center to be on either rows or columns. You'd have to teach the user to 1) Right Click-"Show" pertinent Cost Center (copy-from CC and Copy-to CC's), 2) Highlight cells to be copied, and 3) Edit > Copy Across/Copy Down
> [EASY] Classic Control C-Control V: limited of course by number of cells.
> [Effortful] Create a Copy action. Have user input line items to drop down both the copy-from Cost Center and copy-to Cost Center. Prepare a saved view filtering the copy-from Cost Center information, plus the line item with the copy-to Cost Center. Create an import from this saved view to the Input Module.
> [Business Process Improvement] Consider creating profiles with the information needed (same input line items as the input module), but on a different list that is not cost center. Users can then map a Cost Center to a profile and information can be looked-up from the profile
1. Create one system module for the selection of Cost center
2. Create one more without Cost center dimension & other dimension with be same as your input module.
Write a formula pointing to your Input module, here
INP_Cost Center by Account.SKF Selection[LOOKUP: SYS_ Selection.Cost Center Selection]
3. Create a new module which is same as your input module and write a formula pointing to step 2 module.
Now this is your formula driven module, here I have create one save view to import the data to our Input module by applying one filter cost center <> sys_selection->cost center (even not required, it will override the same data)
4. Create an Import action to transfer the same data to input module.
Note: This approach will depend on the size of your input module because we are duplicating one module.