You can maintain a separate Condition types like PR00/PR01/PR02
(with calculation type as Percentage for second and third condition types and assign the from column for these two with step number of PR00)
Make these two condition types as statistical with some accounting key assigned--maintain some GL in VKOA for these two condition types(alternatively you can try with accruals field in V/06)
Please update if any issues.
Phanikumar