Double check the 'set on order quantities from purchase order history' setting is set. Also note that only POs with no arrived date, or a future arrived date are applied. If the arrived date is in the past it wont be. If POs in an API connected system have been edited, the Refresh Purchase Orders option will need to be selected when re syncing.
If you have uploaded your order amounts via CSV you will need to press "Recalculate" on the order plan once you've finished uploading for the amounts to take effect and your order quantities to be recalculated.
NOTE: Unleashed By default uses the "On Purchase" field from the Stock data. Cin7 uses the "Incoming" field. These take precedence. The PO's will only be used if these values are not set.