Solution : https://service.sap.com/sap/support/notes/438291 (SAP Service marketplace login required)
Key words : 
planned order conversion, terms conversion, planned order, production order, basic dates, shift start, planning table, repetitive manufacturing, longer starts, exact times
Related Notes : 
       
| 480472 | Convertng plannd orders:Basic finsh date by 1 day too early | 
| 447451 | Basic finish date is moved in planned order | 
| 441202 | Customizing Planned order: Scheduling type with times | 
| 438362 | Plnd order: Adjusting basic dates in cap.requirmnts planning | 
| 304510 | APO integration and planned order conversion in R/3 |