Four buckets per location, not one.
Physical (units actually on the shelf), Reserved (units held for paid but unfulfilled orders), In-transit (units on a transfer between two locations) and Damaged (units removed from sellable stock). Every quantity you see anywhere in the system is one of these — no ambiguity, no double-counting.
Transfers that leave a paper trail.
Move stock between locations with a two-step transfer: source location commits units to in-transit, destination location receives them into physical. Every step is dated, timestamped, tied to a user. Discrepancies raise a variance you can investigate, not swallow.
Purchase orders that close the loop.
Create a PO to a supplier, receive it against physical stock (in full or partial), reconcile the vendor invoice against what you actually received. Landed cost — freight, duty, per-unit — rolls into COGS automatically so your margin numbers are real, not aspirational.
Counts that don't stop the store.
Cycle count a category or an aisle at a time without closing the location. Variances post to a review queue for a manager to approve or investigate. Full inventory snapshots are archived, so you can prove what you had on any given day months later.