Solution : https://service.sap.com/sap/support/notes/340092 (SAP Service marketplace login required)
Key words : 
reference field   proposalfif_no_vbrevk   -->    type        char1             spacefif_no_vbreve   -->    type        char1             spacefif_no_vbrevr   -->    type        char1             space 5, ref   short textfif_vbrevk_no_sort type        char1       space, ref   short textfif_vbreve_no_sort type        char1      space, ref   short textfif_vbrevr_no_sort type        char1      space, ref   short textfif_no_sort        type        char3      space, additional key words standard revenue recognition, 6c import parameter   type spec, 6c import parameter       type spec, field  proposal  optional  pass, respective function modules receive
Related Notes : 
       
| 395117 | Performance problem while processing SD documents | 
| 359557 | Long runtimes when saving deliveries w/o reference document | 
| 338126 | Faster processing of different tables | 
| 337299 | Better DB access fr control, revenue and reference table | 
| 333465 | |
| 317545 | Improved reading control lines during posting line creation | 
| 316001 | Improved reading and processing of billing document items | 
| 118743 | Collective note performance in SD |