Business Problem

Sometimes an employee or operator will start a count in the morning and not apply said count until the evening or the next day. During the time that the count is sitting in the "Draft" state, the location continues to sell chicken sandwiches and fries and real life inventory depletes. When the count is finally applied, the system on hand value in the count for any given item is updated by the value in the count and all the depletion is lost. CFA would like to explore a way to account for this user behavior and maintain a more accurate system inventory.

Right now, the best idea for solving this problem (thanks to Sree Surapaneni) is to take the recorded on hand value when the user starts a count and subtract that from the on hand value when the count is applied. Then, take the delta provided by that equation and add it to the user entered value in the count again on count apply. This should account for the depletion while the count is in a draft state.

Possible Recalculation Formula:

User Entered Item Count Value at Count "Apply" + ( "On Hand" Value when the count was started - Count Apply "On Hand" Value)

Information Needed

We know that the network and system experiences heavy traffic and usage at the end of every month as CFA locations perform and apply end of month inventory counts. We should assume that all CFA locations will apply their end of month counts at the exact same time on the exact same day. With this in mind:

How does applying a count work now from a backend perspective?
What are the performance costs to recalculating the on hand inventory of all the locations at the same time?
Will the system be frustrating or unusable?
Is there a risk of losing user entered data due to performance issues?
If the performance costs are too high, what are some additional ideas for solving this problem for CFA?