How to highlight table cells whose value has changed from initial value

We want to highlight those table cells whose value has changed from initial value. For Ex:

Table with initial values :

ITEM      Alloc(%)
======= =======
Item1     10
------  -------
Item2     30
------  -------
Item3     60
------  -------

Table with changed value from 10 => 20 for item1 :

ITEM      Alloc(%)
======= =======
Item1     20
------  -------
Item2     30
------  -------
Item3     60
------  -------

One option I can think is to give some background color to changed cell i.e. cell with value 20 in above table.

Usecase: We have to allocate some cash in % to list of items and provide effective date (which is seperate date picker outside table) for those allocations. Once effective date reached, allocations become active. this completes our one workflow. Now another user can use the above set of allocations as base values on same set of items, and change some/all values based on their need. Here comes our requirement to highlight the changed values and on hovering over it user can still see the active values.

Once this workflow completes, new becomes active and the active one move to inactive state.

Expected amount of changed cells ? Majority of cells expected to be changed. In example have one column but in actual can have multiple columns with same behavior. Time at which change is irrelevant ? Changes will be irrelevent once template becomes active or on completion of workflow. At how many changes notification is obselete ? There is no limit on how may times user allowed to change. Can be saved multiple times as well.

You can think of a webpage having table with editable cells for user to fill allocations. Along side save (save as draft) and submit button (to move to next step in workflow)

Is there any better way I can show it ?

Thanks in advance.