COGS Vs Revenue

Hi Team,

This is very basic question probably that i am asking. But I am trying to understand the significance of COGS (based on item cost) Vs Revenue (based on sales price) from accounting user point of view.

Once COGS recognition happens balance shifts from DCOGS to COGS. This is calculated as (Shipped Qty * Unit Cost).

Once AR invoice and receipt is done, revenue account gets hit. This is calculated as (Transaction Qty * sales price).

What is the significance of calculating COGS considering item cost and revenue considering sales price ? And is there any way that we can reconcile it ?