If you're adding records via forms as you should be then this should be solvable with a main form/subform design. I'm assuming that since sku field is in both tables, the data is related somehow. If not, forget this answer. If you add record for Phil, the subform would be blank when you land on Phil record in main form. However, you must base main form on a query with an outer join (one that gives you all records from API table and related records from other table). Perhaps research form/subform if not familiar with the setup, but create the main form query before creating any forms IMO.
The more we hear silence, the more we begin to think about our value in this universe.
Paraphrase of Professor Brian Cox.