Also, please note that whether or not an absence quota can be manually created depends on the configuration in v_556a_b. So confirm the below:
1) This table is identical in Dev & Qty for your quota type
2) If you check the table, you'd see that the configuration is based on ES grouping & PS grouping for time quota types.
So confirm that for all ES groupings and PS groupings, the radio button 'No generation' is selected in this table.