This is the correct way to adjust stock quantity on hand. You shouldn’t adjust the QOH quite often. But for newly created items, you should do purchase order and receiving instead. Otherwise you will have cost calculation problems later on for reporting and accounting.
Another way to adjust inventory is through inventory count. To do a quick spot snapshot inventory count: http://support.woopos.com/knowledge-base/generating-inventory-snapshots/
If you have lots of items to count, you should use a scanner. Or import a list through Excel or CSV file.