we have a client that wants to process inventory counts with multiple units of measure for the same item e.g. case, box, each I tried in sandbox and seems ok just want to confirm there are no issues e.g 1- Item 1040 UOM: Case 2- Item 1040 UOM: Box 3- Item 1040 UOM: Each Since it is converting back to base unit am I assuming it is ok?

Yes, I assume you just run Netsuite inventory, not a WMS or anything like that. Be aware of searches, quantity is always showing in base unit, quantity in transaction unit shows it in the unit from the order line.