Solution : https://service.sap.com/sap/support/notes/1159281 (SAP Service marketplace login required)
Key words :
customer relationship management -> transactions -> basic settings -> billing plan -> define billing plan types, billing periods billing datejan 1st - jan 31st, specific key date belong logically, 2010mar 1st - mar 31st, 2010jul 1st - jul 31st, 2010aug 1st - aug 31st, 2010feb 1st - feb 28th, 2010apr 1st - apr 30th, 2010jun 1st - jun 30th, billing plan items
Related Notes :
| 1524988 | Grouping not possible if several tax dates are required |
| 1158055 | Tax date for periodic billing plan items wrong |
| 1158012 | Service rendered date for periodic billing plan items wrong |